Power supply subsystem for powering a node over communication cabling

ABSTRACT

A power supply subsystem configured for connection between a LAN switch and at least one node, the power supply subsystem providing electrical power to the at least node over communication cabling, the power supply subsystem comprising: a management and control unit; at least one port for connection to a LAN switch; a combiner combining power into the communication cabling substantially without interfering with data communication between the LAN switch and the at least one node; and current limiting circuitry controlling current of the power delivered into the communication cabling via the combiner, wherein the management and control unit is operative to interrogate the at least one node to which it is intended to transmit power over the communication cabling in order to determine whether the node&#39;s characteristics allow it to receive power over the communication cabling.

REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation of U.S. patent applicationSer. No. 10/218,739 filed Aug. 13, 2002 which is a continuation of U.S.patent application Ser. No. 09/365,584 filed Aug. 2, 1999 issued as U.S.patent Ser. No. 6,473,608, which claims priority from U.S. ProvisionalPatent Application Ser. No. 60/115,628 filed Jan. 12, 1999 and is acontinuation-in-part of U.S. patent application Ser. No. 09/293,343filed Apr. 16, 1999 issued as U.S. patent Ser. No. 6,643,566. The entirecontent of each of the above mentioned applications and patents areincorporated herein by reference.

FIELD OF THE INVENTION

[0002] The present invention relates to structured cabling systems andmore particularly to structured cabling systems used in local areanetworks supplying power to at least one node.

BACKGROUND OF THE INVENTION

[0003] Structured cabling systems are well known for use ininstitutional infrastructure. Such systems provide a standardized yetflexible platform for a dynamic communications environment. Typicallystructure cabling systems employ twisted copper pairs which areinstalled in accordance with predetermined criteria. Structured cablingsystems are conventionally employed for telephone, data communications,as well as for alarms, security and access control applications.

SUMMARY OF THE INVENTION

[0004] The present invention seeks to provide an enhanced structuredcabling system and local area network employing such a system.

[0005] There is thus provided in accordance with a preferred embodimentof the present invention a local area network including a hub, aplurality of nodes, communication cabling connecting the plurality ofnodes to the hub for providing data communication; and a power supplydistributor operative to provide at least some operating power to atleast some of the plurality of nodes via the communication cabling.

[0006] Further in accordance with a preferred embodiment of the presentinvention the communication cabling includes at least part of astructured cabling system.

[0007] Still further in accordance with a preferred embodiment of thepresent invention the power supply distributor is located within thehub.

[0008] Additionally in accordance with a preferred embodiment of thepresent invention the power supply distributor is located outside thehub.

[0009] Moreover in accordance with a preferred embodiment of the presentinvention the power supply distributor is located partially within thehub and partially outside the hub.

[0010] Still further in accordance with a preferred embodiment of thepresent invention the operating power supplied by said power supplydistributor to at least-some of said plurality nodes via saidcommunication cabling includes backup power.

[0011] Additionally in accordance with a preferred embodiment of thepresent invention the hub includes a data communication concentrator,the power supply distributor includes a combiner, and the communicationcabling connects the data communication concentrator via the combiner tothe nodes.

[0012] Sill further in accordance with a preferred embodiment of thepresent invention the hub includes a data communication concentrator andwherein the power supply distributor is also located within the hub.

[0013] Additionally in accordance with a preferred embodiment of thepresent invention the hub includes a data communication concentrator andwherein the power supply distributor is also located within the hub andincludes a power supply and a combiner, the combiner coupling power fromthe power supply to the communication cabling which also carries datafrom the data communication concentrator.

[0014] Preferably the data communication concentrator comprises a LANswitch which functions as a data communication switch/repeater.

[0015] Additionally in accordance with a preferred embodiment of thepresent invention the plurality of nodes includes at least one of thefollowing types of nodes: wireless LAN access points, emergency lightingsystem elements, paging loudspeakers, CCTV cameras, alarm sensors, doorentry sensors, access control units, laptop computers, IP telephones,hubs, switches, routers, monitors and memory backup units for PCs andworkstations.

[0016] Still further in accordance with a preferred embodiment of thepresent invention the hub includes a data communication concentrator thepower supply distributor includes a combiner and a power supply, thecommunication cabling connects the data communication concentrator viathe combiner to the nodes, and the combiner includes a plurality ofcouplers, each of which is connected to an output of the power supply.

[0017] Further in accordance with a preferred embodiment of the presentinvention the hub includes a data communication concentrator, the powersupply distributor includes a combiner and a power supply, thecommunication cabling connects the data communication concentrator viathe combiner to the nodes, and the combiner comprises a plurality ofcouplers and a plurality of filters, each coupler being connected via afilter to an output of the power supply.

[0018] Still further according to a preferred embodiment of the presentinvention the hub includes a data communication concentrator, the powersupply distributor includes a combiner and a power supply, thecommunication cabling connects the data communication concentrator viathe combiner to the nodes, and the combiner includes a plurality ofcouplers and a plurality of filters and a plurality of smart powerallocation and reporting circuits (SPEARs), each coupler being connectedvia a filter and a SPEAR to an output of the power supply.

[0019] Moreover in accordance with a preferred embodiment of the presentinvention the hub includes a data communication concentrator, the powersupply distributor includes a combiner and a power supply, and the powersupply includes a power failure backup facility.

[0020] Additionally or alternatively the hub includes a datacommunication concentrator; the power supply distributor includes acombiner and a power supply, the communication cabling connects the datacommunication concentrator via the combiner to the nodes, and thecombiner comprises a plurality of couplers and a plurality of filters,each coupler being connected via a filter to an output of the powersupply.

[0021] Moreover according to a preferred embodiment of the presentinvention the hub includes a data communication concentrator, the powersupply distributor includes a combiner and a power supply, thecommunication cabling connects the data communication concentrator viathe combiner to the nodes, and the combiner includes a plurality ofcouplers and a plurality of filters and a plurality of smart powerallocation and reporting circuits (SPEARs), each coupler being connectedvia a filter and a SPEAR to an output of the power supply.

[0022] Preferably the hub includes a data communication concentrator,the power supply distributor includes a combiner and a power supply, thecommunication cabling connects the data communication concentrator viathe combiner to the nodes, and the combiner includes a plurality ofcouplers and a plurality of filters, each coupler being connected via afilter to an output of the power supply.

[0023] Additionally or alternatively the hub includes a datacommunication concentrator, the power supply distributor includes acombiner and a power supply, the communication cabling connects the datacommunication concentrator via the combiner to the nodes, and thecombiner comprises a plurality of couplers and a plurality of filtersand a plurality of smart power allocation and reporting circuits(SPEARs), each coupler being connected via a filter and a SPEAR to anoutput of the power supply.

[0024] Preferably the hub includes a data communication concentrator,the power supply distributor includes a combiner and a power supply, thecommunication cabling connects the data communication concentrator viathe combiner to the nodes, and the combiner includes a plurality ofcouplers and a plurality of filters, each coupler being connected via afilter to an output of the power supply.

[0025] Additionally or alternatively the hub includes a datacommunication concentrator, the power supply distributor includes acombiner and a power supply, the communication cabling connects the datacommunication concentrator via the combiner to the nodes, and thecombiner includes a plurality of couplers and a plurality of filters anda plurality of smart power allocation and reporting circuits (SPEARs),each coupler being connected via a filter and a SPEAR to an output ofthe power supply.

[0026] Further in accordance with a preferred embodiment of the presentinvention the power supply distributor is operative to provideelectrical power along the communication cabling without unacceptabledegradation of the digital communication.

[0027] Still further in accordance with a preferred embodiment of thepresent invention the communication cabling comprises at least onetwisted wire pair connected to each node and wherein power istransmitted over a twisted wire pair along which data is alsotransmitted.

[0028] Preferably the hub includes a data communication concentrator,the power supply distributor includes a power supply interface and apower supply, the communication cabling connects the data communicationconcentrator via the power supply interface to the nodes, and powersupply interface includes a plurality of filters and a plurality ofsmart power allocation and reporting circuits (SPEARs), each filterbeing connected via a SPEAR to an output of the power supply.

[0029] Additionally in accordance with a preferred embodiment of thepresent invention the communication cabling comprises at least twotwisted wire pairs connected to each node and wherein power istransmitted over a twisted wire pair different from that along whichdata is transmitted.

[0030] Preferably the hub includes a data communication concentrator,the power supply distributor includes a power supply interface and apower supply, the communication cabling connects the data communicationconcentrator via the power supply interface to the nodes, and the powersupply interface includes a plurality of filters and a plurality ofsmart power allocation and reporting circuits (SPEARs), each filterbeing connected via a SPEAR to an output of the power supply.

[0031] Still further in accordance with a preferred embodiment of thepresent invention the hub includes a data communication concentrator,the power supply distributor includes a combiner and a power supply, thecommunication cabling connects the data communication concentrator viathe combiner to the nodes, the combiner includes a plurality of couplersand a plurality of filters and a plurality of smart power allocation andreporting circuits (SPEARs), each coupler being connected via a filterand a SPEAR to an output of the power supply, and each coupler has atleast two ports, one of which is connected to a port of the datacommunication concentrator and the other of which is connected, viacommunication cabling, to one of the plurality of nodes.

[0032] There is also provided in accordance with a preferred embodimentof the present invention a local area network node for use in a localarea network including a hub, a plurality of nodes, communicationcabling connecting the plurality of nodes to the hub for providingdigital communication and a power supply distributor operative toprovide at least some operating power to at least some of the pluralityof nodes via the hub and the communication cabling, the local areanetwork node including a communications cabling interface receiving bothpower and data and separately providing power to a node power input anddata to a node data input.

[0033] Further in accordance with a preferred embodiment of the presentinvention the communications cabling interface is internal to at leastone of the plurality of nodes.

[0034] Still further in accordance with a preferred embodiment of thepresent invention the communications cabling interface is external to atleast one of the plurality of nodes.

[0035] Additionally in accordance with a preferred embodiment of thepresent invention the power supply distributor is operative to provideelectrical power along the communication cabling without unacceptabledegradation of the digital communication.

[0036] Still further in accordance with a preferred embodiment of thepresent invention the communication cabling includes at least onetwisted wire pair connected to each node and wherein power istransmitted over a twisted wire pair along which data is alsotransmitted.

[0037] Additionally in accordance with a preferred embodiment of thepresent invention the communication cabling includes at least twotwisted wire pairs connected to each node and wherein power istransmitted over a twisted wire pair different from that along whichdata is transmitted.

[0038] Preferably the power supply distributor is operative to provideelectrical power along the communication cabling without unacceptabledegradation of the digital communication.

[0039] Additionally the communication cabling may include at least onetwisted wire pair connected to each node and wherein power istransmitted over a twisted wire pair along which data is alsotransmitted.

[0040] Further more in accordance with a preferred embodiment of thepresent invention the communication cabling includes at least twotwisted wire pairs connected to each node and wherein power istransmitted over a twisted wire pair different from that along whichdata is transmitted.

[0041] Preferably the power supply distributor is operative to provideelectrical power along the communication cabling without unacceptabledegradation of the digital communication.

[0042] Further in accordance with a preferred embodiment of the presentinvention the communication cabling includes at least one twisted wirepair connected to each node and wherein power is transmitted over atwisted wire pair along which data is also transmitted.

[0043] Still further in accordance with a preferred embodiment of thepresent invention the communication cabling includes at least twotwisted wire pairs connected to each node and wherein power istransmitted over a twisted wire pair different from that along whichdata is transmitted.

[0044] Moreover in accordance with a preferred embodiment of the presentinvention the hub includes a data communication concentrator, the powersupply distributor includes a combiner, a management and control unitand a power supply, the communication cabling connects said datacommunication concentrator via the combiner to the node, the combinerincludes a plurality of couplers and a plurality of filters and aplurality of smart power allocation and reporting circuits (SPEARs),each coupler being connected via a filter and a SPEAR to an output ofsaid power supply, and the SPEAR is operative to report to themanagement and control unit the current consumption of a node connectedthereto.

[0045] Further in accordance with a preferred embodiment of the presentinvention the hub includes a data communication concentrator, the powersupply distributor includes a combiner and a power supply, thecommunication cabling connects the data communication concentrator viathe combiner to the nodes, the combiner comprises a plurality ofcouplers and a plurality of filters and a plurality of smart powerallocation and reporting circuits (SPEARs), each coupler being connectedvia a filter and a SPEAR to an output of the power supply, and the SPEARis operative to limit the maximum current supplied to a node connectedthereto.

[0046] Alternatively according to a preferred embodiment of the presentinvention the hub includes a data communication concentrator, the powersupply distributor includes a combiner and a power supply, thecommunication cabling connects the data communication concentrator viathe combiner to the nodes, the combiner includes a plurality of couplersand a plurality of filters and a plurality of smart power allocation andreporting circuits (SPEARs), each coupler being connected via a filterand a SPEAR to an output of the power supply, and the SPEAR is operativeto automatically disconnect a node connected thereto displaying anovercurrent condition following elapse of a programmably predeterminedperiod of time.

[0047] Additionally in accordance with a preferred embodiment of thepresent invention the hub includes a data communication concentrator,the power supply distributor includes a combiner and a power supply, thecommunication cabling connects the data communication concentrator viathe combiner to the nodes, the combiner includes a plurality of couplersand a plurality of filters and a plurality of smart power allocation andreporting circuits (SPEARs), each coupler being connected via a filterand a SPEAR to an output of the power supply, and the SPEAR is operativeto automatically disconnect power from a node connected theretodisplaying an overcurrent condition following elapse of a programmablypredetermined period of time and to automatically reconnect the node topower thereafter when it no longer displays the overcurrent condition.

[0048] Moreover in accordance with a preferred embodiment of the presentinvention the hub includes a data communication concentrator, the powersupply distributor includes a combiner and a power supply, thecommunication cabling connects said data communication concentrator viathe combiner to the nodes, the combiner includes a plurality of couplersand a plurality of filters and a plurality of smart power allocation andreporting circuits (SPEARs), each coupler being connected via a filterand a SPEAR to an output of the power supply, and the SPEAR includes acurrent sensor which receives a voltage input Vin from a power supplyand generates a signal which is proportional to the current passingtherethrough, and a multiplicity of comparators receiving the signalfrom the current sensor and also receiving a reference voltage Vref fromrespective reference voltage sources.

[0049] Preferably the reference voltage sources are programmablereference voltage sources and receive control inputs from management &control circuits.

[0050] Additionally the outputs of the multiplicity of comparators maybe supplied to a current limiter and switch which receives input voltageVin via the current sensor and provides a current-limited voltage outputVout.

[0051] Furthermore the outputs of the comparators are supplied tomanagement & control circuits to serve as monitoring inputs providinginformation regarding the DC current flowing through the SPEAR.

[0052] Additionally in accordance with a preferred embodiment of thepresent invention the hub includes a data communication concentrator,the power supply distributor includes a combiner and a power supply, thecommunication cabling connects the data communication concentrator viathe combiner to the nodes, and the combiner includes a plurality ofcouplers each of which includes at least a pair of transformers, eachhaving a center tap at a secondary thereof via which the DC voltage isfed to each wire of a twisted pair connected thereto.

[0053] Further in accordance with a preferred embodiment of the presentinvention the hub includes a data communication concentrator, the powersupply distributor includes a combiner and a power supply, thecommunication cabling connects the data communication concentrator viathe combiner to the nodes, and the combiner includes a plurality ofcouplers each of which includes at least one transformer, which ischaracterized in that it includes a secondary which is split into twoseparate windings and a capacitor which is connected between the twoseparate windings and which effectively connects the two windings inseries for high frequency signals, but effectively isolates the twowindings for DC.

[0054] Still further in accordance with a preferred embodiment of thepresent invention the hub includes a data communication concentrator,the power supply distributor includes a combiner a power supply, thecommunication cabling connects the data communication concentrator viathe combiner to the nodes, and the combiner includes a pair ofcapacitors which effectively block DC from reaching the datacommunication concentrator.

[0055] Still further in accordance with a preferred embodiment of thepresent invention the hub includes a data communication concentrator,the power supply distributor includes a combiner and a power supply, thecommunication cabling connects the data communication concentrator viathe combiner to the nodes, and the combiner comprises two pairs ofcapacitors which effectively block DC from reaching the datacommunication concentrator.

[0056] Additionally in accordance with a preferred embodiment of thepresent invention the hub includes a data communication concentrator,the power supply distributor includes a combiner and a power supply, thecommunication cabling connects the data communication concentrator viathe combiner to the nodes, and the combiner includes a self-balancingcapacitor-less and transformer-less common mode coupling circuit.

[0057] Preferably the communications cabling interface includes aseparator and a pair of transformers, each having a center tap at aprimary thereof via which the DC voltage is extracted from each wire ofa twisted pair connected thereto.

[0058] Additionally or alternatively the communications cablinginterface includes a separator including at least one transformer, whichis characterized in that it includes a primary which is split into twoseparate windings and a capacitor which is connected between the twoseparate windings and which effectively connects the two windings inseries for high frequency signals, but effectively isolates the twowindings for DC.

[0059] Furthermore the communications cabling interface includes aseparator comprising a pair of capacitors which effectively block DCfrom reaching a data input of a node connected thereto.

[0060] Additionally in accordance with a preferred embodiment of thepresent invention the communications cabling interface includes aseparator comprising two pairs of capacitors which effectively block DCfrom reaching a data input of a node connected thereto.

[0061] Additionally or alternatively the communications cablinginterface includes a separator includes a self-balancing capacitor-lessand transformer-less common mode coupling circuit.

[0062] There is further provided in accordance with a preferredembodiment of the present invention a local area network including ahub, a plurality of nodes, a communication cabling connecting saidplurality of nodes to the hub for providing data communication, and apower supply distributor operative to provide at least some operatingpower to at least some of the plurality of nodes via the communicationcabling, the power supply distributor including power managementfunctionality.

[0063] Preferably the power supply distributor includes a powermanagement & control unit which monitors and controls the power suppliedto various nodes via the communications cabling.

[0064] Additionally in accordance with a preferred embodiment of thepresent invention the power supply distributor includes a managementworkstation which is operative to govern the operation of the powermanagement & control unit.

[0065] Preferably the management workstation governs the operation ofmultiple power management & control units.

[0066] Moreover in accordance with a preferred embodiment of the presentinvention the power management & control unit communicates with variousnodes via a data communication concentrator thereby to govern theircurrent mode of power usage.

[0067] Further in accordance with a preferred embodiment of the presentinvention the power management & control unit communicates with variousnodes via control messages which are decoded at the nodes and areemployed for controlling whether full or partial functionality isprovided thereat.

[0068] Still further in accordance with a preferred embodiment of thepresent invention the power management & control unit senses that mainspower to said power supply distributor is not available and sends acontrol message to cause nodes to operate in a backup or reduced powermode.

[0069] Preferably the node includes essential circuitry, which isrequired for both full functionality and reduced functionalityoperation, and non-essential circuitry, which is not required forreduced functionality operation.

[0070] There is also provided with yet another preferred embodiment ofthe present invention a local area network power supply distributor foruse in a local area network including a hub, a plurality of nodes andcommunication cabling connecting the plurality of nodes to a hub forproviding digital communication therebetween, the power supplydistributor being operative to provide at least some operating power toat least some of said plurality of nodes via the communication cabling.

[0071] Further in accordance with a preferred embodiment of the presentinvention the supply distributor is located within the hub.

[0072] Still further in accordance with a preferred embodiment of thepresent invention the power supply distributor is located outside thehub. Alternatively the power supply distributor is located partiallywithin the hub and partially outside the hub.

[0073] Additionally in accordance with a preferred embodiment of thepresent invention the operating power supplied by the power supplydistributor to at least some of the plurality nodes via thecommunication cabling includes backup power.

[0074] Still further in accordance with a preferred embodiment of thepresent invention the hub includes a data communication concentrator,the power supply distributor includes a combiner, and the communicationcabling connects the data communication concentrator via the combiner tothe nodes.

[0075] Moreover in accordance with a preferred embodiment of the presentinvention the hub includes a data communication concentrator and whereinthe power supply distributor is also located within the hub.

[0076] Still further in accordance with a preferred embodiment of thepresent invention the hub includes a data communication concentrator andwherein said power supply distributor is also located within the hub andincludes a power supply and a combiner, the combiner coupling power fromthe power supply to the communication cabling which also carries datafrom the data communication concentrator.

[0077] Preferably the combiner includes a plurality of couplers, each ofwhich is connected to an output of the power supply.

[0078] Additionally in accordance with a preferred embodiment of thepresent invention the combiner includes a plurality of couplers and aplurality of filters, each coupler being connected via a filter to anoutput of the power supply.

[0079] Furthermore the combiner may also include a plurality of couplersand a plurality of filters and a plurality of smart power allocation andreporting circuits (SPEARs), each coupler being connected via a filterand a SPEAR to an output of the power supply.

[0080] Additionally in accordance with a preferred embodiment of thepresent invention the power supply distributor includes a power supply,and the power supply includes a power failure backup facility.

[0081] Still further in accordance with a preferred embodiment of thepresent invention the combiner includes a plurality of couplers and aplurality of filters, each coupler being connected via a filter to anoutput of the power supply.

[0082] Preferably the combiner includes a plurality of couplers and aplurality of filters and a plurality of smart power allocation andreporting circuits (SPEARs), each coupler being connected via a filterand a SPEAR to an output of the power supply.

[0083] Moreover in accordance with a preferred embodiment of the presentinvention the combiner includes a plurality of couplers and a pluralityof filters, each coupler being connected via a filter to an output of apower supply.

[0084] Additionally the combiner may also include a plurality ofcouplers and a plurality of filters and a plurality of smart powerallocation and reporting circuits (SPEARs), each coupler being connectedvia a filter and a SPEAR to an output of the power supply.

[0085] Furthermore the combiner may also include a plurality of couplersand a plurality of filters, each coupler being connected via a filter toan output of a power supply.

[0086] Moreover in accordance with a preferred embodiment of the presentinvention the power supply distributor is operative to provideelectrical power along the communication cabling without unacceptabledegradation of the digital communication.

[0087] Further in accordance with a preferred embodiment of the presentinvention the communication cabling includes at least one twisted wirepair connected to each node and wherein power is transmitted over atwisted wire pair along which data is also transmitted.

[0088] Preferably the power supply distributor includes a power supplyinterface and a power supply, the communication cabling connects thedata communication concentrator via the power supply interface to thenodes, and the power supply interface includes a plurality of filtersand a plurality of smart power allocation and reporting circuits(SPEARs), each filter being connected via a SPEAR to an output of thepower supply.

[0089] Additionally in accordance with a preferred embodiment of thepresent invention the communication cabling includes at least twotwisted wire pairs connected to each node and wherein power istransmitted over a twisted wire pair different from that along whichdata is transmitted.

[0090] Moreover in accordance with a preferred embodiment of the presentinvention the hub includes a data communication concentrator, the powersupply distributor includes a power supply interface and a power supply,the communication cabling connects the data communication concentratorvia the power supply interface to said nodes, and the power supplyinterface includes a plurality of filters and a plurality of smart powerallocation and reporting circuits (SPEARs), each filter being connectedvia a SPEAR to an output of the power supply.

[0091] Still further in accordance with a preferred embodiment of thepresent invention the hub includes a data communication concentrator,the power supply distributor includes a combiner and a power supply, thecommunication cabling connects the data communication concentrator viathe combiner to the nodes, the combiner includes a plurality of couplersand a plurality of filters and a plurality of smart power allocation andreporting circuits (SPEARs), each coupler being connected via a filterand a SPEAR to an output of the power supply, and each coupler has atleast two ports, one of which is connected to a port of the datacommunication concentrator and the other of which is connected, viacommunication cabling, to one of the plurality of nodes.

[0092] Additionally in accordance with a preferred embodiment of thepresent invention the hub includes a data communication concentrator,the power supply distributor includes a combiner, a management andcontrol unit and a power supply, the communication cabling connects saiddata communication concentrator via the combiner to the nodes, thecombiner includes a plurality of couplers and a plurality of filters anda plurality of smart power allocation and reporting circuits (SPEARs),each coupler being connected via a filter and a SPEAR to an output ofthe power supply, and the SPEAR is operative to report to the managementand control unit the current consumption of a node connected thereto.

[0093] Still further in accordance with a preferred embodiment of thepresent invention the hub includes a data communication concentrator,the power supply distributor includes a combiner and a power supply, thecommunication cabling connects the data communication concentrator viathe combiner to the nodes, the combiner includes a plurality of couplersand a plurality of filters and a plurality of smart power allocation andreporting circuits (SPEARs), each coupler being connected via a filterand a SPEAR to an output of the power supply, and the SPEAR is operativeto limit the maximum current supplied to a node connected thereto.

[0094] Still further in accordance with a preferred embodiment of thepresent invention the hub includes a data communication concentrator,the power supply distributor includes a combiner and a power supply, thecommunication cabling connects the data communication concentrator viathe combiner to the nodes, the combiner includes a plurality of couplersand a plurality of filters and a plurality of smart power allocation andreporting circuits (SPEARs), each coupler being connected via a filterand a SPEAR to an output of the power supply, and the SPEAR is operativeto automatically disconnect a node connected thereto displaying anovercurrent condition following elapse of a programmably predeterminedperiod of time.

[0095] Additionally in accordance with a preferred embodiment of thepresent invention the hub includes a data communication concentrator,the power supply distributor includes a combiner and a power supply, thecommunication cabling connects the data communication concentrator viathe combiner to the nodes, the combiner includes a plurality of couplersand a plurality of filters and a plurality of smart power allocation andreporting circuits (SPEARs), each coupler being connected via a filterand a SPEAR to an output of the power supply, and the SPEAR is operativeto automatically disconnect power from a node connected theretodisplaying an overcurrent condition following elapse of a programmablypredetermined period of time and to automatically reconnect the node topower thereafter when it no longer displays the overcurrent condition.

[0096] Still further in, accordance with a preferred embodiment of thepresent invention the hub includes a data communication concentrator,the power supply distributor includes a combiner and a power-supply, thecommunication cabling connects the, data communication concentrator viathe combiner to the nodes, the combiner includes a plurality of couplersand a plurality of filters and a plurality of smart power allocation andreporting circuits (SPEARs), each coupler being connected via a filterand a SPEAR to an output of the power supply, and the SPEAR includes acurrent sensor which receives a voltage input Vin from a power supplyand generates a signal which is proportional to the current passingtherethrough, and a multiplicity of comparators receiving the signalfrom the current sensor and also receiving a reference voltage Vref fromrespective reference voltage sources.

[0097] Preferably the reference voltage sources are programmablereference voltage sources and receive control inputs from management &control circuits.

[0098] Additionally the outputs of the multiplicity of comparators maybe supplied to a current limiter and switch which receives input voltageVin via the current sensor and provides a current-limited voltage outputVout.

[0099] Furthermore the outputs of the comparators may be supplied tomanagement & control circuits to serve as monitoring inputs providinginformation regarding the DC current flowing through the SPEAR.

[0100] Still further in accordance with a preferred embodiment of thepresent invention the hub includes a data communication concentrator,the power supply distributor includes a combiner and a power supply, thecommunication cabling connects the data communication concentrator viathe combiner to the nodes, and the combiner includes plurality ofcouplers each of which includes at least a pair of transformers, eachhaving a center tap at a secondary thereof via which the DC voltage isfed to each wire of a twisted pair connected thereto.

[0101] Additionally in accordance with a preferred embodiment of thepresent invention the hub includes a data communication concentrator,the power supply distributor includes a combiner and a power supply, thecommunication cabling connects the data communication concentrator viathe combiner to the nodes, and the combiner includes a plurality ofcouplers each of which includes at least one transformer, which ischaracterized in that it includes a secondary which is split into twoseparate windings and a capacitor which is connected between the twoseparate windings and which effectively connects the two windings inseries for high frequency signals, but effectively isolates the twowindings for DC.

[0102] Further in accordance with a preferred embodiment of the presentinvention the hub includes a data communication concentrator, the powersupply distributor includes a combiner and a power supply, thecommunication cabling connects the data communication concentrator viathe combiner to the nodes, and the combiner includes a pair ofcapacitors which effectively block DC from reaching the datacommunication concentrator.

[0103] Still further in accordance with a preferred embodiment of thepresent invention the hub includes a data communication concentrator,the power supply distributor includes a combiner and a power supply, thecommunication cabling connects the data communication concentrator viathe combiner to the nodes, and the combiner comprises two pairs ofcapacitors which effectively block DC from reaching the datacommunication concentrator.

[0104] Additionally in accordance with a preferred embodiment of thepresent invention the hub includes a data communication concentrator,the power supply distributor includes a combiner and a power supply, thecommunication cabling connects the data communication concentrator viathe combiner to the nodes, and the combiner comprises a self-balancingcapacitor-less and transformer-less common mode coupling circuit.

[0105] Preferably the power supply distributor includes power managementfunctionality.

[0106] Additionally the power supply distributor may include a powermanagement & control unit which monitors and controls the power suppliedto various nodes via the communications cabling.

[0107] Furthermore the power supply distributor may include a managementworkstation which is operative to govern the operation of said powermanagement & control unit.

[0108] Furthermore in accordance with a preferred embodiment of thepresent invention the management workstation governs the operation ofmultiple power management & control units.

[0109] Preferably the power management & control unit communicates withvarious nodes via a data communication concentrator thereby to governtheir current mode of power usage.

[0110] Additionally in accordance with a preferred embodiment of thepresent invention the power management & control unit communicates withvarious nodes via control messages which are decoded at the nodes andare employed for controlling whether full or partial functionality isprovided thereat.

[0111] Additionally the power management & control unit senses thatmains power to the power supply distributor is not available and sends acontrol message to cause nodes to operate in a backup or reduced powermode.

[0112] Furthermore the node includes essential circuitry, which isrequired for both full functionality and reduced functionalityoperation, and non-essential circuitry, which is not required forreduced functionality operation.

BRIEF DESCRIPTION OF THE DRAWINGS

[0113] The present invention will be understood and appreciated morefully from the following detailed description, taken in conjunction withthe drawings in which:

[0114]FIGS. 1A and 1B are simplified block diagram illustrations of twoalternative embodiments of a local area network including a power supplyoperative to provide electrical power to local area network nodes overcommunication cabling constructed and operative in accordance with onepreferred embodiment of the present invention;

[0115]FIGS. 2A and 2B are simplified block diagram illustrations of twoalternative embodiments of a local area network including a power supplyoperative to provide electrical power to local area network nodes overcommunication cabling constructed and operative in accordance withanother preferred embodiment of the present invention;

[0116]FIGS. 3A & 3B are simplified block diagrams of hubs useful in theembodiments of FIGS. 1A and 1B respectively;

[0117]FIGS. 4A & 4B are simplified block diagrams of hubs and powersupply subsystems useful in the embodiments of FIGS. 2A & 2Brespectively;

[0118]FIG. 5 is a simplified block diagram illustration of a smart powerallocation and reporting circuit useful in the embodiments of FIGS. 3A,3B, 4A and 4B;

[0119]FIG. 6 is a simplified schematic illustration of the embodiment ofFIG. 5;

[0120]FIGS. 7A & 7B are simplified block diagram illustrations of LANnode interface circuits useful in the embodiments of FIGS. 1A & 2A andFIGS. 1B & 2B respectively;

[0121]FIGS. 8A-8G are simplified block diagram and schematicillustrations of various embodiments of a combiner useful in theembodiments of FIGS. 3A and 4A;

[0122]FIGS. 9A-9G are simplified block diagram and schematicillustrations of various embodiments of a separator useful in theembodiments of FIGS. 1A, 2A & 7A in combination with combiners of FIGS.8A-8G;

[0123]FIGS. 10A & 10B are simplified block diagram illustrations of twoalternative embodiments of a communications network including powersupply and management over communications cabling constructed andoperative in accordance with a preferred embodiment of the presentinvention;

[0124]FIGS. 11A & 11B are simplified block diagram illustrations of twoalternative embodiments of a local area network including power supplyand management unit operative to provide electrical power to local areanetwork nodes over communication cabling;

[0125]FIGS. 12A & 12B are simplified block diagram illustrations of ahub useful in the embodiments of FIGS. 10A & 10B respectively;

[0126]FIGS. 13A & 13B are simplified block diagram illustrations of ahub and a power supply and management subsystem useful in theembodiments of FIG. 11A & 11B respectively;

[0127]FIGS. 14A & 14B are simplified block diagrams of two differentnode configurations useful in the embodiments of FIGS. 10A, 10B, 11A &11B;

[0128]FIG. 15 is a simplified block diagram of a node configurationwhich combines the features shown in FIGS. 14A & 14B;

[0129]FIG. 16 is a generalized flowchart illustrating power managementin both normal operation and reduced power modes of the networks ofFIGS. 10A, 10B, 11A & 11B;

[0130]FIG. 17 is a generalized flowchart illustrating one step in theflowchart of FIG. 16;

[0131]FIGS. 18A and 18B together are a generalized flowchartillustrating a preferred embodiment of the interrogation and initialpower supply functionality which appears in FIG. 17;

[0132]FIGS. 19A, 19B, 19C and 19D are generalized flowcharts eachillustrating one possible mechanism for full or no functionalityoperation in an involuntary power management step in the flowchart ofFIG. 16;

[0133]FIGS. 20A, 20B, 20C and 20D are generalized flowcharts eachillustrating one possible mechanism for full or reduced functionalityoperation in an involuntary power management step in the flowchart ofFIG. 16;

[0134]FIGS. 21A, 21B, 21C and 21D are generalized flowcharts eachillustrating one possible mechanism for node initiated sleep modeoperation in a voluntary power management step in the flowchart of FIG.16;

[0135]FIGS. 22A, 22B, 22C and 22D are generalized flowcharts eachillustrating one possible mechanism for hub initiated sleep modeoperation in a voluntary power management step in the flowchart of FIG.16;

[0136]FIGS. 23A, 23B, 23C and 23D are generalized flowcharts eachillustrating one possible mechanism for full or no functionalityprioritized operation in a voluntary power management step in theflowchart of FIG. 16; and

[0137]FIGS. 24A, 24B, 24C and 24D are generalized flowcharts eachillustrating one possible mechanism for full or reduced functionalityprioritized operation in a voluntary power management step in theflowchart of FIG. 16.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0138] Reference is now made to FIG. 1A, which is a simplified blockdiagram illustration of a local area network constructed and operativein accordance with a preferred embodiment of the present invention. Asseen in FIG. 1A, there is provided a local area network (LAN) comprisinga hub 10 which is coupled, by cabling 11, preferably a structuredcabling system, to a plurality of LAN nodes, such as a desktop computer12, a web camera 14, a facsimile machine 16, a LAN telephone, also knownas an IP telephone 18, a computer 20 and a server 22.

[0139] Cabling 11 is preferably conventional LAN cabling having fourpairs of twisted copper wires cabled together under a common jacket. Inthe embodiment of FIG. 1A, as will be described hereinbelow, at leastone of the pairs of twisted copper wires is employed for transmittingboth data and electrical power to nodes of the network. Typically twosuch pairs are employed for transmitting both data and electrical poweralong each line connecting a hub to each node, while one such paircarries data only and a fourth pair is maintained as a spare and carriesneither data nor power.

[0140] In accordance with a preferred embodiment of the presentinvention there is provided a power supply subsystem 30 which isoperative to provide at least some operating or backup power to at leastsome of said plurality of nodes via the hub 10 and the communicationcabling connecting the hub to various LAN nodes.

[0141] In the illustrated embodiment of FIG. 1A, subsystem 30 is locatedwithin the hub 10 and includes a power supply 32 which suppliesoperating power and/or backup power to various LAN nodes via thecommunication cabling. The communication cabling connects a LAN switch34 via a combiner 36 to the various LAN nodes. The combiner coupleselectrical power from the power supply 32 along the communicationcabling to at least some of the LAN nodes. Bidirectional datacommunications from LAN switch 34 pass through the combiner 36,substantially without interference.

[0142] It is seen that the communication cabling 11 from the hub 10 tothe desktop computer 12, facsimile machine 16 and computer 20 carriesboth data and backup power, while the communication cabling from the hub10 to the hub camera 14 and LAN telephone 18 carries both data andoperating power and the communication cabling from the hub to the server22 carries only data, in a typically LAN arrangement constructed andoperative in accordance with a preferred embodiment of the presentinvention.

[0143] It is a particular feature of the embodiment of FIG. 1A that bothdata and power are carried on the same twisted copper pair.

[0144] It is appreciated that each of the LAN nodes 12-20 which receivespower over the communication cabling includes a separator for separatingthe electrical power from the data. In the illustrated embodiment ofFIG. 1A, the separators are typically internal to the respective nodesand are not separately designated, it being appreciated thatalternatively discrete separators may be employed.

[0145] Reference is now made to FIG. 1B, which is a simplified blockdiagram illustration of a local area network constructed and operativein accordance with another preferred embodiment of the presentinvention. As seen in FIG. 1B, there is provided a local area network(LAN) comprising a hub 60 which is coupled, by cabling 61, preferably astructured cabling system, to a plurality of LAN nodes, such as adesktop computer 62, a web camera 64, a facsimile machine 66, a LANtelephone, also known as an IP telephone 68, a computer 70 and a server72.

[0146] Cabling 61 is preferably conventional LAN cabling having fourpairs of twisted copper wires cabled together under a common jacket. Inthe embodiment of FIG. 1B, in contrast to the arrangement describedabove with respect to FIG. 1A and as will be described hereinbelow, atleast one of the pairs of twisted copper wires is employed only fortransmitting electrical power to nodes of the network and at least oneof the pairs of twisted copper wires is employed only for transmittingdata. Typically two such pairs are employed for transmitting data onlyand two such pairs are employed only for supplying electrical poweralong each line connecting a hub to each node.

[0147] In accordance with a preferred embodiment of the presentinvention there is provided a power supply subsystem 80 which isoperative to provide at least some operating or backup power to at leastsome of said plurality of nodes via the hub 60 and the communicationcabling 61 connecting the hub to various LAN nodes.

[0148] In the illustrated embodiment of FIG. 1B, subsystem 80 is locatedwithin the hub 60 and includes a power supply 82 which suppliesoperating power and/or backup power to various LAN nodes via thecommunication cabling. The communication cabling connects a LAN switch84 via a power supply interface 86 to the various LAN nodes. The powersupply interface 86 distributes electrical power from the power supply82, along twisted pairs of the communication cabling 61 which are notused for carrying data, to at least some of the LAN nodes. Bidirectionaldata communications from LAN switch 84 pass through the power supplyinterface 86, substantially without interference.

[0149] It is seen that the communication cabling 61 from the hub 60 tothe desktop computer 62, facsimile machine 66 and computer 70 carriesboth data and backup power along separate twisted pairs, while thecommunication cabling 61 from the hub 60 to the hub camera 64 and LANtelephone 68 carries both data and operating power along separatetwisted pairs and the communication cabling 61 from the hub 60 to theserver 72 carries only data, in a typically LAN arrangement constructedand operative in accordance with a preferred embodiment of the presentinvention.

[0150] It is a particular feature of the embodiment of FIG. 1B that dataand power are carried on separate twisted copper pairs of eachcommunication cabling line.

[0151] It is appreciated that each of the LAN nodes 62-70 which receivespower over the communication cabling 61 includes a connector forconnecting the twisted pairs carrying electrical power to a node powersupply and separately connecting the twisted pairs carrying data to adata input of the node. In the illustrated embodiment of FIG. 1B, theconnectors are typically internal to the respective nodes and are notseparately designated, it being appreciated that alternatively discreteconnectors may be employed.

[0152] It is appreciated that FIGS. 1A and 1B illustrates twoembodiments of a system providing electric power to plural LAN nodes viaa hub and communication cabling connecting the hub to various LAN nodes.Another two embodiments of a system providing electric power to pluralLAN nodes via a hub and communication cabling connecting the hub tovarious LAN nodes are illustrated in FIGS. 2A & 2B. FIGS. 2A & 2Billustrate a local area network including a power supply operative toprovide electrical power to local area network nodes over communicationcabling.

[0153] In the illustrated embodiment of FIG. 2A, a conventional hub 100does not provide electrical power over the communication cabling 101 anda power supply subsystem 130 is located externally of hub 100 andincludes a power supply 132 which supplies operating power and/or backuppower to various LAN nodes via the communication cabling 101. Thecommunication cabling connects a LAN switch 134 of conventional hub 100to a combiner 136 in power supply subsystem 130 and connects thecombiner to the various LAN nodes. The combiner 136 provides electricalpower from the power supply 132 along the communication cabling to atleast some of the LAN nodes. Bidirectional data communications from LANswitch 134 pass through the combiner 136, substantially withoutinterference.

[0154] Cabling 101 is preferably conventional LAN cabling having fourpairs of twisted copper wires cabled together under a common jacket. Inthe embodiment of FIG. 2A, as will be described hereinbelow, at leastone of the pairs of twisted copper wires is employed for transmittingboth data and electrical power to nodes of the network. Typically twosuch pairs are employed for transmitting both data and electrical poweralong each line connecting the power supply sub-system 130 to each node,while one such pair carries data only and a fourth pair is maintained asa spare and carries neither data nor power.

[0155] It is seen that the communication cabling 101 from the powersupply sub-system 130 to the desktop computer 112, facsimile machine 116and computer 120 carries both data and backup power, while thecommunication cabling from the power supply sub-system 130 to the hubcamera 114 and LAN telephone 118 carries both data and operating powerand the communication cabling from the hub 100 to the server 122 carriesonly data and may, but need not pass through subsystem 130, in atypically LAN arrangement constructed and operative in accordance with apreferred embodiment of the present invention.

[0156] It is a particular feature of the embodiment of FIG. 2A that bothdata and power are carried on the same twisted copper pair.

[0157] In the illustrated embodiment of FIG. 2A, each of the LAN nodes112-120 which receives power is provided with an external separator forseparating the data from the electrical power coupled to thecommunication cabling. The external separators associated withrespective nodes 112-120 are designated by respective reference numbers142-149. Each such separator has a communication cabling input andseparate data and power outputs. It is appreciated that some or all ofthe nodes 112-120 may alternatively be provided with internal separatorsand that some or all of the nodes 112-120 may be provided with externalseparators.

[0158] It is appreciated that in addition to the LAN nodes describedhereinabove, the present invention is useful with any other suitablenodes such as, for example, wireless LAN access points, emergencylighting system elements, paging loudspeakers, CCTV cameras, alarmsensors, door entry sensors, access control units, laptop computers,network elements such as hubs, switches and routers, monitors and memorybackup units for PCs and workstations.

[0159] In the illustrated embodiment of FIG. 2B, a conventional hub 150does not provide electrical power over the communication cabling 151 anda power supply subsystem 180 is located externally of hub 150 andincludes a power supply 182 which supplies operating power and/or backuppower to various LAN nodes via the communication cabling 151. Thecommunication cabling connects a LAN switch 184 of conventional hub 150to a power supply interface 186 in power supply subsystem 180 andconnects the power supply interface 186 to the various LAN nodes. Thepower supply interface distributes electrical power from the powersupply 182 along the communication cabling to at least some of the LANnodes. Bidirectional data communications from LAN switch 184 passthrough the power supply interface 186, substantially withoutinterference.

[0160] Cabling 151 is preferably conventional LAN cabling having fourpairs of twisted copper wires cabled together under a common jacket. Inthe embodiment of FIG. 2B, in contrast to the arrangement describedabove with respect to FIG. 2A and as will be described hereinbelow, atleast one of the pairs of twisted copper wires is employed only fortransmitting electrical power to nodes of the network and at least oneof the pairs of twisted copper wires is employed only for transmittingdata. Typically two such pairs are employed for transmitting data onlyand two such pairs are employed only for supplying electrical poweralong each line connecting a hub to each node.

[0161] It is seen that the communication cabling 151 from the hub 150 tothe desktop computer 162, facsimile machine 166 and computer 170 carriesboth data and backup power, while the communication cabling from the hub150 to the hub camera 164 and LAN telephone 168 carries both data andoperating power and the communication cabling from the hub 150 to theserver 172 carries only data and may, but need not pass throughsubsystem 180, in a typically LAN arrangement constructed and operativein accordance with a preferred embodiment of the present invention.

[0162] It is a particular feature of the embodiment of FIG. 2B that dataand power are carried on separate twisted copper pairs of eachcommunication cabling line.

[0163] In the illustrated embodiment of FIG. 2B, each of the LAN nodes162-170 which receives power is provided with an external connector forseparately providing data and electrical power from the communicationcabling. The external connector associated with respective nodes 162-170are designated by respective reference numbers 192-199. Each suchconnector has a communication cabling input and separate data and poweroutputs. It is appreciated that some or all of the nodes 162-170 mayalternatively be provided with internal connectors and that some or allof the nodes 162-170 may be provided with external connectors.

[0164] It is appreciated that in addition to the LAN nodes describedhereinabove, the present invention is useful with any other suitablenodes such as, for example, wireless LAN access points, emergencylighting system elements, paging loudspeakers, CCTV cameras, alarmsensors, door entry sensors, access control units, laptop computers,network elements, such as hubs, switches and routers, monitors andmemory backup units for PCs and workstations.

[0165] Reference is now made to FIG. 3A, which is a simplified blockdiagram of a hub, such as hub 10, useful in the embodiment of FIG. 1A.Hub 10 preferably comprises a conventional, commercially available, LANswitch 34 which functions as a data communication switch/repeater and iscoupled to combiner 36. Combiner 36 typically comprises a plurality ofcouplers 220, each of which is connected via a filter 222 to a smartpower allocation and reporting circuit (SPEAR) 224. Each SPEAR 224 isconnected to power supply 32 for receiving electrical power therefrom.It is appreciated that power supply 32 may be physically locatedexternally of the hub 10. Power supply 32 may be provided with a powerfailure backup facility, such as a battery connection.

[0166] Each coupler 220 has two ports, one of which is preferablyconnected to a port of LAN switch 34 and the other of which ispreferably connected, via communication cabling, to a LAN node.

[0167] Couplers 220 are preferably operative to couple electrical powerto the communication cabling substantially without interfering with thedata communication therealong.

[0168] Filters 222 are preferably operative to avoid unwanted interportand interpair coupling, commonly known as “crosstalk” and to block noisefrom the power supply 32 from reaching the communication cabling.

[0169] A central management and control subsystem 226, typicallyembodied in a microcontroller, preferably controls the operation of thepower supply 32, the LAN switch 34, the couplers 220, the filters 222and the SPEARs 224.

[0170] Reference is now made to FIG. 3B, which is a simplified blockdiagram of a hub, such as hub 60, useful in the embodiment of FIG. 1B.Hub 60 preferably comprises a conventional, commercially available, LANswitch 84 which functions as a data communication switch/repeater and iscoupled to power supply interface 86. Power supply interface 86typically comprises a plurality of filters 272, each connected to asmart power allocation and reporting circuit (SPEAR) 274. Each SPEAR 274is connected to power supply 82 for receiving electrical powertherefrom. It is appreciated that power supply 82 may be physicallylocated externally of the hub 60. Power supply 82 may be provided with apower failure backup facility, such as a battery connection.

[0171] Filters 272 are preferably operative to avoid unwanted interportcoupling, commonly known as “crosstalk” and to block noise from thepower supply 82 from reaching the communication cabling.

[0172] A central management and control subsystem 276, typicallyembodied in a microcontroller, preferably controls the operation of thepower supply 82, the LAN switch 84, the filters 272 and the SPEARs 274.

[0173] It is seen that in the embodiment of FIG. 3B, couplers are notprovided inasmuch as power and data are transmitted over separatetwisted pairs. The data carried on conductors via the power supplyinterface is substantially unaffected by the operation of the powersupply interface.

[0174] Reference is now made to FIG. 4A, which is a simplified blockdiagram of hub 100 and the power supply subsystem 130 employed in theembodiment of FIG. 2A. Hub 100 preferably comprises a conventional,commercially available, LAN switch 134 which functions as a datacommunication switch/repeater and is coupled to combiner 136 formingpart of power supply subsystem 130. Combiner 136 typically comprises aplurality of couplers 320, each of which is connected via a filter 322to a smart power allocation and reporting circuit (SPEAR) 324. EachSPEAR 324 is connected to power supply 132 (FIG. 2A) for receivingelectrical power therefrom. It is appreciated that power supply 132 maybe physically located externally of the power supply subsystem 130.Power supply 132 may be provided with a power failure backup facility,such as a battery connection.

[0175] Each coupler 320 has two ports, one of which is preferablyconnected to a port of LAN switch 134 and the other of which ispreferably connected, via communication cabling, to a LAN node.

[0176] Couplers 320 are preferably operative to couple electrical powerto the communication cabling substantially without interfering with thedata communication therealong.

[0177] Filters 322 are preferably operative to avoid unwanted interportand interpair coupling, commonly known as “crosstalk” and to block noisefrom the power supply 132 from reaching the communication cabling.

[0178] A central management and control subsystem 326, typicallyembodied in a microcontroller, preferably controls the operation of thepower supply 132, the couplers 320, the filters 322 and the SPEARs 324.

[0179] Reference is now made to FIG. 4B, which is a simplified blockdiagram of hub 150 and the power supply subsystem 180 employed in theembodiment of FIG. 2B. Hub 150 preferably comprises a conventional,commercially available, LAN switch 184 which functions as a datacommunication switch/repeater and is coupled to power supply interface186 forming part of power supply subsystem 180. Power supply interface186 typically comprises a plurality of filters 372 each coupled to asmart power allocation and reporting circuit (SPEAR) 374. Each SPEAR 374is connected to power supply 182 (FIG. 2B) for receiving electricalpower therefrom. It is appreciated that power supply 182 may bephysically located externally of the power supply subsystem 180. Powersupply 182 may be provided with a power failure backup facility, such asa battery connection.

[0180] Filters 372 are preferably operative to avoid unwanted interportand interpair coupling, commonly known as “crosstalk” and to block noisefrom the power supply 182 from reaching the communication cabling.

[0181] A central management and control subsystem 376, typicallyembodied in a microcontroller, preferably controls the operation of thepower supply 182, filters 372 and the SPEARs 374.

[0182] It is seen that in the embodiment of FIG. 4B, couplers are notprovided inasmuch as power and data are transmitted over separatetwisted pairs. The data carried on conductors via the power supplyinterface is substantially unaffected by the operation of the powersupply interface.

[0183] It is appreciated that power supply 32 (FIG. 3A), power supply 82(FIG. 3B), power supply 132 (FIG. 4A) and power supply 182 (FIG. 4B)provide output power to SPEARs 224 (FIG. 3A), SPEARs 274 (FIG. 3B), 324(FIG. 4A) and 374 (FIG. 4B) respectively along a pair of conductors, oneof which is designated as a positive conductor and indicated by (+) andthe other of which is designated as a negative conductor and indicatedby (−). The voltages supplied to the respective positive and negativeconductors are designated respectively as +Vin and −Vin. The differencetherebetween is designated as Vin.

[0184] Reference is now made to FIG. 5, which is a simplified blockdiagram illustration of a smart power allocation and reporting circuit(SPEAR) 400 useful in the embodiments of FIGS. 3A, 3B and FIGS. 4A, 4Bparticularly when DC current is coupled to the communication cabling.

[0185] SPEAR 400 preferably comprises a current sensor 402 whichreceives a voltage input +Vin from a power supply and generates a signalwhich is proportional to the current passing therethrough. A voltageinput-Vin received from the power supply 32 (FIG. 3A), 82 (FIG. 3B), 132(FIG. 4A) or 182 (FIG. 4B) provides a voltage output-Vout which istypically unchanged from voltage input-Vin.

[0186] The output of current sensor 402 is supplied to a multiplicity ofcomparators 404 which also receive respective reference voltages Vreffrom respective programmable reference voltage sources 406, typicallyimplemented in A/D converters. Programmable reference voltage sources406 receive control inputs from management & control circuits 226 (FIG.3A), 276 (FIG. 3B), 326 (FIG. 4A) and 376 (FIG. 4B) preferably via a bus407. Alternatively, voltage sources 406 need not be programmable.

[0187] The outputs of comparators 404 are supplied to a current limiterand switch 408 which receives input voltage Vin via the current sensor402 and provides a current-limited voltage output Vout. Output voltages+Vout and −Vout are applied as inputs to an A/D converter 409 whichoutputs a digital indication of Vout, which is the difference between+Vout and-Vout, to the management & control circuits 226 (FIG. 3A), 276(FIG. 3B), 326 (FIG. 4A) and 376 (FIG. 4B) preferably via bus 407. Theoutputs of comparators 404 are supplied to management & control circuits226 (FIG. 3A), 276 (FIG. 3B), 326 (FIG. 4A) and 376 (FIG. 4B) preferablyvia bus 407 to serve as monitoring inputs providing informationregarding the DC current flowing through the SPEAR.

[0188] The outputs of some of comparators 404 are supplied directly tocurrent limiter and switch 408, while the outputs of others ofcomparators 404 are supplied thereto via a timer 410 and a flip/flop412. The comparators whose outputs are supplied directly to currentlimiter and switch 408 provide immediate current limiting at arelatively high threshold, while the comparators whose outputs aresupplied to current limiter and switch 408 via timer 410 and flip/flop412 provide delayed action current cut-off at a relatively lowthreshold.

[0189] Flip-flop 412 is responsive to external inputs which enableremote control of the operation of the current limiter and switch 408 bythe management & control circuits 226 (FIG. 3A), 276 (FIG. 3B), 326(FIG. 4A) and 376 (FIG. 4B) via bus 407.

[0190] It is appreciated that the above described SPEAR circuitry mayalso be operated on the negative lead. In such a case a short-leadwould-be connected between the Vin and the Vout.

[0191] It is further appreciated that the components of the SPEAR mayalso be organize in an alternative sequence.

[0192] Reference is now made FIG. 6, which is a simplified schematicillustration of a preferred implementation of the embodiment of FIG. 5.Inasmuch as identical reference numerals are employed in both FIGS. 5and 6, the schematic illustration of FIG. 6. is believed to beself-explanatory and therefore, for the sake of conciseness, noadditional textual description thereof is provided herein.

[0193] Reference is now made to FIG. 7A, which is a simplified blockdiagram illustration of a LAN node interface circuit useful in theembodiments of FIGS. 1A and 2A for example as external separators142-149. It is appreciated that the circuitry of FIG. 7A alternativelymay be built-in to LAN nodes, as shown, for example in FIG. 1A.

[0194]FIG. 7A shows typical constituent elements of a network node 500,including a data transceiver 502, a mains-fed power supply 504 andvarious other elements 506 depending on the functionality of the node.The interface circuitry typically comprises a separator 508 which isoperative to receive data and electrical power over communicationcabling and to provide a data output to the data transceiver 502 and aseparate power output to a communications cabling-fed power supply 510,preferably forming part of network node 500, which preferably powers thedata transceiver 502 and possibly any other suitable circuitry.

[0195] Reference is now made to FIG. 7B, which is a simplified blockdiagram illustration of a LAN node interface circuit useful in theembodiments of FIGS. 1B and 2B for example as external connectors192-199. It is appreciated that the circuitry of FIG. 7B alternativelymay be built-in to LAN nodes, as shown, for example in FIG. 1B.

[0196]FIG. 7B shows typical constituent elements of a network node 550,including a data transceiver 552, a mains-fed power supply 554 andvarious other elements 556 depending on the functionality of the node.The interface circuitry typically comprises a connector 558 which isoperative to receive data and electrical power over communicationcabling and to provide a data output to the data transceiver 552 and aseparate power output to a communications cabling-fed power supply 560,preferably forming part of network node 550, which preferably powers thedata transceiver 552 and possibly any other suitable circuitry.

[0197] Reference is FIGS. 8A-8E, which are simplified block diagramillustrations of various embodiments of a coupler useful in theembodiments of FIGS. 3A and 4A. The various embodiments have the commonpurpose of coupling DC power to the communication cabling withoutupsetting the balance therealong, while producing a minimal change inthe line impedance thereof and preventing saturation or burnout of linetransformers coupled thereto.

[0198]FIG. 8A describes a coupler 600, such as coupler 220 (FIG. 3A) orcoupler 320 (FIG. 4A) suitable for use with a LAN in accordance with apreferred embodiment of the present invention and which includes a pairof additional transformers 610 for each channel. Transformers 610 aretypically 1:1 transformers which are characterized in that they includea center tap at the secondary via which the DC voltage is fed to bothwires of a twisted pair.

[0199] This structure maintains the balance of the line and preventscore saturation. This structure also has the advantage that due to thefact that the same voltage is carried on both wires of the twisted pairsimultaneously, the occurrence of a short circuit therealong will notcause a power overload. An additional advantage of this structure isthat it will not cause burnout of a LAN node which is not speciallyadapted for receive power over the twisted pair.

[0200]FIG. 8B describes a coupler 620, such as coupler 220 (FIG. 3A) orcoupler 320 (FIG. 4A) suitable for use with a LAN in accordance with apreferred embodiment of the present invention and which includes a pairof additional transformers 630 for each channel. Transformers 630 aretypically 1:1 transformers which are characterized in that they includea secondary 632 which is split into two separate windings 634 and 636. Acapacitor 640 is connected between windings 634 and 636. The capacitoreffectively connects the two windings in series for high frequencysignals, such as data signals, but effectively isolates the two windingsfor DC.

[0201] This structure enables the two windings to carry respectivepositive and negative voltages via the same twisted pair. An advantageof this structure is that it applies a net zero DC current via thetwisted pair and thus eliminates the magnetic field that would otherwisehave existed had the twisted pair carried DC current in the samedirections.

[0202]FIG. 8C describes a coupler 650, such as coupler 220 (FIG. 3A) orcoupler 320 (FIG. 4A) suitable for use with a LAN in accordance with apreferred embodiment of the present invention and which includes a pairof capacitors 660 which effectively block DC from reaching the LANswitch. This structure is relatively simple and does not require anadditional transformer.

[0203]FIG. 8D describes a coupler 670, such as coupler 220 (FIG. 3A) orcoupler 320 (FIG. 4A) suitable for use with a LAN in accordance with apreferred embodiment of the present invention and which includes twopairs of capacitors 680 and 690 which effectively block DC from reachingthe LAN switch. This structure is also relatively simple and does notrequire an additional transformer.

[0204] This structure also has the advantage that due to the fact thatthe same voltage is carried on both wires of the twisted pairsimultaneously, the occurrence of a short circuit therealong will notcause a power overload. An additional advantage of this structure isthat it will not cause burnout of a LAN node which is not speciallyadapted for receive power over the twisted pair.

[0205]FIG. 8E describes a coupler 700, such as coupler 220 (FIG. 3A) orcoupler 320 (FIG. 4A) suitable for use with a LAN in accordance with apreferred embodiment of the present invention and which is aself-balancing common mode coupling circuit. Combiner 700 comprises twopairs of adjustable active balancing circuits 702 and 704, which areoperative in conjunction with respective sensing and control circuits706 and 708.

[0206] It is a particular feature of the embodiment of FIG. 8E that thetwo pairs of adjustable active balancing circuits 702 and 704, which areoperative in conjunction with respective sensing and control circuits706 and 708 are operative to maintain precisely identical voltages oneach of the two wires comprising a twisted pair coupled thereto.

[0207] Normally the output of a LAN switch is coupled to communicationcabling via an isolation transformer 710, which is not part of thecoupler 700. When precisely identical voltages, as aforesaid, areapplied to each of the two wires comprising the twisted pair, there isno DC voltage across the secondary windings of the isolation transformer710 and thus no DC current flows therethrough. This obviates the needfor DC isolating capacitors and thus improves the balancing andimpedance matching behavior of the combiner.

[0208] It is appreciated that whereas in a theoretically ideal systemthere would not be any need for active balancing as provided in theembodiment of FIG. 8E, in reality due to variations in the DC resistancealong the entire communication cabling system, the DC voltages on eachof the two wires of the twisted pair would not be identical in theabsence of active balancing, thus creating a DC voltage drop across thesecondary of transformer 710 which could cause either saturation orburnout of transformer 710.

[0209] Reference is now made FIG. 8F, which is a simplified schematicillustration of a preferred implementation of the embodiment of FIG. 8E.Inasmuch as identical reference numerals are employed in both FIGS. 8Eand 8F, the schematic illustration of FIG. 8F is believed to beself-explanatory and therefore, for the sake of conciseness, noadditional textual description thereof is provided herein.

[0210] Reference is now made FIG. 8G, which is a simplified schematicillustration of a preferred implementation of the embodiment of FIG. 8E.Inasmuch as identical reference numerals are employed in both FIGS. 8Eand 8G, the schematic illustration of FIG. 8G is believed to beself-explanatory and therefore, for the sake of conciseness, noadditional textual description thereof is provided herein.

[0211] Reference is now made to FIGS. 9A-9G which are simplified blockdiagram and schematic illustrations of various embodiments of aseparator useful in the embodiments of FIGS. 1A, 2A & 7A preferably incombination with the respective combiners of FIGS. 8A-8G.

[0212] In addition to the components included in FIGS. 9A to 9G, theseseparators may also include appropriate filters to avoid interpair andinterport crosstalk.

[0213] The various embodiments have the common purpose of decoupling DCpower from the communication cabling without upsetting the balancetherealong, while producing a minimal change in the line impedancethereof and preventing saturation or burnout of line transformerscoupled thereto.

[0214]FIG. 9A describes a separator 1600, such as separator 142 (FIG.2A), suitable for use with a LAN in accordance with a preferredembodiment of the present invention and which includes a pair ofadditional transformers 1610 for each channel. Transformers 1610 aretypically 1:1 transformers which are characterized in that they includea center tap at the primary via which the DC voltage is extracted fromboth wires of a twisted pair.

[0215] This structure maintains the balance of the line and preventscore saturation. This structure also has the advantage that due to thefact that the same voltage is carried on both wires of the twisted pairsimultaneously, the occurrence of a short circuit therealong will notcause a power overload. An additional advantage of this structure isthat it will not cause burnout of a LAN node which is not speciallyadapted for receive power over the twisted pair.

[0216]FIG. 9B describes a separator 1620, such as separator 142 (FIG.2A) suitable for use with a LAN in accordance with a preferredembodiment of the present invention and which includes a pair ofadditional transformers 1630 for each channel. Transformers 1630 aretypically 1:1 transformers which are characterized in that they includea primary 1632 which is split into two separate windings 1634 and 1636.A capacitor 1640 is connected between windings 1634 and 1636. Thecapacitor effectively connects the two windings in series for highfrequency signals, such as data signals, but effectively isolates thetwo windings for DC.

[0217] This structure enables the two windings to carry respectivepositive and negative voltages via the same twisted pair. An advantageof this structure is that it applies a net zero DC current via thetwisted pair and thus eliminates the magnetic field that would otherwisehave existed had the twisted pair carried DC current in the samedirections.

[0218]FIG. 9C describes a separator 1650, such as separator 142 (FIG.2A), suitable for use with a LAN in accordance with a preferredembodiment of the present invention and which includes a pair ofcapacitors 1660 which effectively block DC from reaching the nodecircuits. This structure is relatively simple and does not require anadditional transformer.

[0219]FIG. 9D describes a separator 1670, such as separator 142 (FIG.2A), suitable for use with a LAN in accordance with a preferredembodiment of the present invention and which includes two pairs ofcapacitors 1680 and 1690 which effectively block DC from reaching thenode circuits. This structure is also relatively simple and does notrequire an additional transformer.

[0220] This structure also has the advantage that due to the fact thatthe same voltage is carried on both wires of the twisted pairsimultaneously, the occurrence of a short circuit therealong will notcause a power overload. An additional advantage of this structure isthat it will not cause burnout of a LAN node which is not speciallyadapted for receive power over the twisted pair.

[0221]FIG. 9E describes a separator 1700, such as separator 142 (FIG.2A), suitable for use with a LAN in accordance with a preferredembodiment of the present invention and which is a self-balancing commonmode coupling circuit. Separator 1700 comprises two pairs of adjustableactive balancing circuits 1702 and 1704, which are operative inconjunction with respective sensing and control circuits 1706 and 1708.

[0222] It is a particular feature of the embodiment of FIG. 9E that thetwo pairs of adjustable active balancing circuits 1702 and 1704, whichare operative in conjunction with respective sensing and controlcircuits 1706 and 1708 are operative to maintain precisely identicalvoltages on each of the two wires comprising a twisted pair coupledthereto.

[0223] Normally the input of a LAN node is coupled to communicationcabling via an isolation transformer 1710, which is not part of theseparator 1700. When precisely identical voltages, as aforesaid, aremaintained on each of the two wires comprising the twisted pair, thereis no DC voltage across the primary windings of the isolationtransformer 1710 and thus no DC current flows therethrough. Thisobviates the need for DC isolating capacitors and thus improves thebalancing and impedance matching behavior of the separator.

[0224] It is appreciated that whereas in a theoretically ideal systemthere would not be any need for active balancing as provided in theembodiment of FIG. 9E, in reality due to variations in the DC resistancealong the entire communication cabling system, the DC voltages on eachof the two wires of the twisted pair would not be identical in theabsence of active balancing, thus creating a DC voltage drop across theprimary of transformer 1710 which could cause either saturation orburnout of transformer 1710.

[0225] Reference is now made FIG. 9F, which is a simplified schematicillustration of part of a preferred implementation of the embodiment ofFIG. 9E, including elements 1702 and 1706 thereof. Inasmuch as identicalreference numerals are employed in both FIGS. 9E and 9F, the schematicillustration of FIG. 9F is believed to be self-explanatory andtherefore, for the sake of conciseness, no additional textualdescription thereof is provided herein.

[0226] Reference is now made FIG. 9G, which is a simplified schematicillustration of part of a preferred implementation of the embodiment ofFIG. 9E, including elements 1704 and 1708 thereof. Inasmuch as identicalreference numerals are employed in both FIGS. 9E and 9G, the schematicillustration of FIG. 9G is believed to be self-explanatory andtherefore, for the sake of conciseness, no additional textualdescription thereof is provided herein.

[0227] The circuits of FIGS. 9F and 9G is provided to ensure that thevoltage is identical on both leads of the twisted pair to which they arecoupled in order to prevent current flow through transformers 1710 (FIG.9E). This is accomplished by the circuits of 9F and 9G by changing thecurrent flowing through the active filters 1702 and 1704 under thecontrol of elements 1706 and 1708 respectively.

[0228] Reference is now made to FIG. 10A, which is a simplified blockdiagram illustration of a communications network including power supplyand management over communications cabling constructed and operative inaccordance with a preferred embodiment of the present invention.

[0229] As seen in FIG. 10A, there is provided a local area network (LAN)comprising a hub 2010 which is coupled, by cabling, preferably astructured cabling system, to a plurality of LAN nodes, such as adesktop computer 2012, a web camera 2014, a facsimile machine 2016, aLAN telephone, also known as an IP telephone 2018, a computer 2020 and aserver 2022.

[0230] In accordance with a preferred embodiment of the presentinvention there is provided a power supply subsystem 2030 which isoperative to provide at least some operating or backup power to at leastsome of said plurality of nodes via the hub 2010 and the communicationcabling connecting the hub to various LAN nodes.

[0231] In the illustrated embodiment of FIG. 10A, subsystem 2030 islocated within the hub 2010 and includes a power supply 2032 whichsupplies operating power and/or backup power to various LAN nodes viathe communication cabling. The communication cabling connects a LANswitch 2034 via a combiner 2036 to the various LAN nodes. The combinercouples electrical power from the power supply 2032 along thecommunication cabling to at least some of the LAN nodes. Bidirectionaldata communications from LAN switch 2034 pass through the combiner 2036,substantially without interference.

[0232] In accordance with a preferred embodiment of the presentinvention, there is provided in hub 2010 a power management & controlunit 2038 which monitors and controls the power supplied by subsystem2030 to the various LAN nodes via the communications cabling. The powermanagement & control unit 2038 preferably communicates with a managementworkstation 2040, preferably via a LAN or a WAN. Management workstation2040 is operative, preferably under the control of an operator, togovern the operation of power management & control unit 2038.

[0233] It is appreciated that a management workstation 2040 may governthe operation of multiple power management & control units 2038. Thepower management & control unit 2038 may also communicate with variousLAN nodes via LAN switch 2034 by providing standard LAN messages to thenodes thereby to govern their current mode of power usage. For example,power management & control unit 2038 may send control messages which aredecoded at the LAN nodes and are employed by controllers in thecircuitry of FIGS. 14A & 14B for controlling whether full or partialfunctionality is provided thereat.

[0234] In one specific case, when the power management & control unit2038 senses that mains power to power supply 2032 is not available, itmay send a control message via LAN switch 2034 to cause the various LANnodes to operate in a backup or reduced power mode.

[0235] It is seen that the communication cabling from the hub 2010 tothe desktop computer 2012, facsimile machine 2016 and computer 2020carries both data and backup power, while the communication cabling fromthe hub 2010 to the hub camera 2014 and LAN telephone 2018 carries bothdata and operating power and the communication cabling from the hub tothe server 2022 carries only data, in a typically LAN arrangementconstructed and operative in accordance with a preferred embodiment ofthe present invention.

[0236] It is appreciated that each of the LAN nodes 2012-2020, whichreceives power over the communication cabling, includes a separator forseparating the electrical power from the data. In the illustratedembodiment of FIG. 10A, the separators are typically internal to therespective nodes and are not separately designated, it being appreciatedthat alternatively discrete separators may be employed.

[0237] It is a particular feature of the embodiment of FIG. 10A thatboth data and power are carried on the same twisted copper pair.

[0238] It is appreciated that FIG. 10A illustrates one embodiment of asystem providing electric power to plural LAN nodes via a hub andcommunication cabling connecting the hub to various LAN nodes. Anotherembodiment of a system providing electric power to plural LAN nodes viaa hub and communication cabling connecting the hub to various LAN nodesis illustrated in FIG. 11A. FIG. 11A illustrates a local area networkincluding a power supply and management unit operative to provideelectrical power to local area network nodes over communication cabling.

[0239] Reference is now made to FIG. 10B, which is a simplified blockdiagram illustration of a communications network including power supplyand management over communications cabling constructed and operative inaccordance with a preferred embodiment of the present invention.

[0240] As seen in FIG. 10B, there is provided a local area network (LAN)comprising a hub 2060 which is coupled, by cabling, preferably astructured cabling system, to a plurality of LAN nodes, such as adesktop computer 2062, a web camera 2064, a facsimile machine 2066, aLAN telephone, also known as an IP telephone 2068, a computer 2070 and aserver 2072.

[0241] In accordance with a preferred embodiment of the presentinvention there is provided a power supply subsystem 2080 which isoperative to provide at least some operating or backup power to at leastsome of said plurality of nodes via the hub 2060 and the communicationcabling connecting the hub to various LAN nodes.

[0242] In the illustrated embodiment of FIG. 10B, subsystem 2080 islocated within the hub 2060 and includes a power supply 2082 whichsupplies operating power and/or backup power to various LAN nodes viathe communication cabling. The communication cabling connects a LANswitch 2084 via a power supply interface 2086 to the various LAN nodes.The power supply interface provides electrical power from the powersupply 2082 along the communication cabling to at least some of the LANnodes. Bidirectional data communications from LAN switch 2084 passthrough the power supply interface 2086, substantially withoutinterference.

[0243] In accordance with a preferred embodiment of the presentinvention, there is provided in hub 2060 a power management & controlunit 2088 which monitors and controls the power supplied by subsystem2080 to the various LAN nodes via the communications cabling. The powermanagement & control unit 2088 preferably communicates with a managementworkstation 2090, preferably via a LAN or a WAN. Management workstation2090 is operative, preferably under the control of an operator, togovern the operation of power management & control unit 2088.

[0244] It is appreciated that a management workstation 2090 may governthe operation of multiple power management & control units 2088. Thepower management & control unit 2088 may also communicate with variousLAN nodes via LAN switch 2084 by providing standard LAN messages to thenodes thereby to govern their current mode of power usage. For example,power management & control unit 2088 may send control messages which aredecoded at the LAN nodes and are employed by controllers in thecircuitry of FIGS. 14A & 14B for controlling whether full or partialfunctionality is provided thereat.

[0245] In one specific case, when the power management & control unit2088 senses that mains power to power supply 2082 is not available, itmay send a control message via LAN switch 2084 to cause the various LANnodes to operate in a backup or reduced power mode.

[0246] It is seen that the communication cabling from the hub 2060 tothe desktop computer 2062, facsimile machine 2066 and computer 2070carries both data and backup power, while the communication cabling fromthe hub 2060 to the hub camera 2064 and LAN telephone 2068 carries bothdata and operating power and the communication cabling from the hub tothe server 2072 carries only data, in a typically LAN arrangementconstructed and operative in accordance with a preferred embodiment ofthe present invention.

[0247] It is appreciated that each of the LAN nodes 2062-2070, whichreceives power over the communication cabling, includes a connector forseparately providing electrical power and data. In the illustratedembodiment of FIG. 10B, the connectors are typically internal to therespective nodes and are not separately designated, it being appreciatedthat alternatively discrete connector may be employed.

[0248] It is a particular feature of the embodiment of FIG. 10B thatdata and power are carried on separate twisted copper pairs of eachcommunication cabling line.

[0249] It is appreciated that FIG. 10B illustrates one embodiment of asystem providing electric power to plural LAN nodes via a hub andcommunication cabling connecting the hub to various LAN nodes. Anotherembodiment of a system providing electric power to plural LAN nodes viaa hub and communication cabling connecting the hub to various LAN nodesis illustrated in FIG. 11B. FIG. 11B illustrates a local area networkincluding a power supply and management unit operative to provideelectrical power to local area network nodes over communication cabling.

[0250] In the illustrated embodiment of FIG. 11A, a conventional hub2100 does not provide electrical power over the communication cablingand a power supply and management subsystem 2130 is located externallyof hub 2100 and includes a power supply 2132 which supplies operatingpower and/or backup power to various LAN nodes via the communicationcabling as well as a power management & control unit 2133.

[0251] The communication cabling connects a LAN switch 2134 ofconventional hub 2100 to a combiner 2136 in power supply and managementsubsystem 2130 and connects the combiner to the various LAN nodes. Thecombiner 2136 couples electrical power from the power supply 2132 alongthe communication cabling to at least some of the LAN nodes.Bidirectional data communications from LAN switch 2134 pass through thecombiner 2136, substantially without interference.

[0252] In accordance with a preferred embodiment of the presentinvention, there is provided in power supply and management subsystem2130 power management & control unit 2133 which monitors and controlsthe power supplied by subsystem 2130 to the various LAN nodes via thecommunications cabling. The power management & control unit 2133preferably communicates with a management workstation 2140, preferablyvia a LAN or a WAN.

[0253] Management workstation 2140 is operative, preferably under thecontrol of an operator, to govern the operation of power management &control unit 2133. It is appreciated that a management workstation 2140may govern the operation of multiple power management & control units2133 and may also govern the operation of multiple hubs 2100.

[0254] It is seen that the communication cabling from the hub 2100 tothe desktop computer 2112, facsimile machine 2116 and computer 2120carries both data and backup power, while the communication cabling fromthe hub 2100 to the hub camera 2114 and LAN telephone 2118 carries bothdata and operating power and the communication cabling from the hub 2100to the server 2122 carries only data and may, but need not pass throughsubsystem 2130, in a typically LAN arrangement constructed and operativein accordance with a preferred embodiment of the present invention.

[0255] In the illustrated embodiment of FIG. 11A, each of the LAN nodes2112-2120 which receives power is provided with an external separatorfor separating the data from the electrical power coupled to thecommunication cabling. The external separators associated withrespective nodes 2112-2120 are designated by respective referencenumbers 2142-2150. Each such separator has a communication cabling inputand separate data and power outputs. It is appreciated that some or allof the nodes 2112-2120 may alternatively be provided with internalseparators and that some or all of the nodes 2112-2120 may be providedwith external separators.

[0256] It is appreciated that in addition to the LAN nodes describedhereinabove, the present invention is useful with any other suitablenodes such as, for example, wireless LAN access points, emergencylighting system elements, paging loudspeakers, CCTV cameras, alarmsensors, door entry sensors, access control units, laptop computers,network elements, such as hubs, switches and routers, monitors andmemory backup units for PCs and workstations.

[0257] In the illustrated embodiment of FIG. 11B, a conventional hub2150 does not provide electrical power over the communication cablingand a power supply and management subsystem 2180 is located externallyof hub 2150 and includes a power supply 2182 which supplies operatingpower and/or backup power to various LAN nodes via the communicationcabling as well as a power management & control unit 2183.

[0258] The communication cabling connects a LAN switch 2184 ofconventional hub 2150 to a power supply interface 2186 in power supplyand management subsystem 2180 and connects the combiner to the variousLAN nodes. The power supply interface 2186 provides electrical powerfrom the power supply 2182 along the communication cabling to at leastsome of the LAN nodes. Bidirectional data communications from LAN switch2184 pass through the power supply interface 2186, substantially withoutinterference.

[0259] In accordance with a preferred embodiment of the presentinvention, there is provided in power supply and management subsystem2180 power management & control unit 2183 which monitors and controlsthe power supplied by subsystem 2180 to the various LAN nodes via thecommunications cabling. The power management & control unit 2183preferably communicates with a management workstation 2190, preferablyvia a LAN or a WAN.

[0260] Management workstation 2190 is operative, preferably under thecontrol of an operator, to govern the operation of power management &control unit 2183. It is appreciated that a management workstation 2190may govern the operation of multiple power management & control units2183 and may also govern the operation of multiple hubs 2150.

[0261] It is seen that the communication cabling from the hub 2150 tothe desktop computer 2162, facsimile machine 2166 and computer 2170carries both data and backup power, while the communication cabling fromthe hub 2150 to the hub camera 2164 and LAN telephone 2168 carries bothdata and operating power and the communication cabling from the hub 2150to the server 2172 carries only data and may, but need not pass throughsubsystem 2180, in a typically LAN arrangement constructed and operativein accordance with a preferred embodiment of the present invention.

[0262] In the illustrated embodiment of FIG. 11B, each of the LAN nodes2162-2170 which receives power is provided with an external connectorfor separately providing data and electrical power from thecommunication cabling. The external connectors associated withrespective nodes 2162-2170 are designated by respective referencenumbers 2192-2199. Each such connector has a communication cabling inputand separate data and power outputs. It is appreciated that some or allof the nodes 2162-2170 may alternatively be provided with internalconnectors and that some or all of the nodes 2162-2170 may be providedwith external connectors.

[0263] It is appreciated that in addition to the LAN nodes describedhereinabove, the present invention is useful with any other suitablenodes such as, for example, wireless LAN access points, emergencylighting system elements, paging loudspeakers, CCTV cameras, alarmsensors, door entry sensors, access control units, laptop computers,network elements, such as hubs, switches and routers, monitors andmemory backup units for PCs and workstations.

[0264] Reference is now made to FIG. 12A, which is a simplified blockdiagram illustration of a hub, such as hub 2010, useful in theembodiment of FIG. 10A. Hub 2010 preferably comprises a conventional,commercially available, LAN switch, such as LAN switch 2034 (FIG. 10A),which functions as a data communication switch/repeater and is coupledto a coupler and filter unit 2037 which includes couplers 220 andfilters 222 as shown in FIG. 3A and forms part of combiner 2036 (FIG.10A).

[0265] The coupler and filter unit 2037 is connected to a plurality ofsmart power allocation and reporting circuits (SPEARs) 2224. Each SPEAR2224 is connected to power supply 2032 (FIG. 10A) for receivingelectrical power therefrom. It is appreciated that power supply 2032 maybe physically located externally of the hub 2010. Power supply 2032 maybe provided with a power failure backup facility, such as a batteryconnection.

[0266] Power management & control unit 2038 (FIG. 10A), preferablyincludes SPEAR controllers 2160 which are preferably connected via a bus2162 to a microprocessor 2164, a memory 2166 and communication circuitry2168, which typically includes a modem. The power management & controlsubsystem 2038 is preferably operative to control the operation of allof the couplers, filters and SPEARs in combiner 2036 as well as tocontrol the operation of the power supply 2032. Power management &control subsystem 2038 preferably communicates with management workstation 2040 (FIG. 10A) in order to enable operator control andmonitoring of the power allocated to the various LAN nodes in variousoperational modes of the system.

[0267] Reference is now made to FIG. 12B, which is a simplified blockdiagram illustration of a hub, such as hub 2060, useful in theembodiment of FIG. 10B. Hub 2060 preferably comprises a conventional,commercially available, LAN switch, such as LAN switch 2084 (FIG. 10B),which functions as a data communication switch/repeater and is coupledto a filter unit 2087 which includes filters 222 as shown in FIG. 3B andforms part of power supply interface 2086 (FIG. 10B).

[0268] The filter unit 2087 is connected to a plurality of smart powerallocation and reporting circuits (SPEARs) 2274. Each SPEAR 2274 isconnected to power supply 2082 (FIG. 10B) for receiving electrical powertherefrom. It is appreciated that power supply 2082 may be physicallylocated externally of the hub 2060. Power supply 2082 may be providedwith a power failure backup facility, such as a battery connection.

[0269] Power management & control unit 2088 (FIG. 10B), preferablyincludes SPEAR controllers 2276 which are preferably connected via a bus2278 to a microprocessor 2280, a memory 2282 and communication circuitry2284, which typically includes a modem. The power management & controlsubsystem 2088 is preferably operative to control the operation of allof the filters and SPEARs in power supply interface 2086 as well as tocontrol the operation of the power supply 2082. Power management &control unit 2088 preferably communicates with management work station2090 (FIG. 10B) in order to enable operator control and monitoring ofthe power allocated to the various LAN nodes in various operationalmodes of the system.

[0270] Reference is now made to FIG. 13A, which is a simplified blockdiagram illustration of a hub and a power supply and managementsubsystem useful in the embodiment of FIG. 11A. Hub 2100 (FIG. 11A)preferably comprises a conventional, commercially available, LAN switch2134 which functions as a data communication switch/repeater and iscoupled to combiner 2136 forming part of power supply subsystem 2130.

[0271] Combiner 2136 includes a coupler and filter unit 2137 whichinclude couplers 320 and filters 322 as shown in FIG. 4A.

[0272] The coupler and filter unit 2137 is connected to a plurality ofsmart power allocation and reporting circuits (SPEARs) 2324. Each SPEAR2324 is connected to power supply 2132 (FIG. 11A) for receivingelectrical power therefrom. It is appreciated that power supply 2132 maybe physically located externally of the power supply and managementsubsystem 2130. Power supply 2132 may be provided with a power failurebackup facility, such as a battery connection.

[0273] Power management & control unit 2133 (FIG. 11A), preferablyincludes SPEAR controllers 2360 which are preferably connected via a bus2362 to a microprocessor 2364, a memory 2366 and communication circuitry2368, which typically includes a modem. The power management & controlunit 2133 is preferably operative to control the operation of all of thecouplers, filters and SPEARs in combiner 2136 as well as to control theoperation of the power supply 2132.

[0274] Power management & control subsystem 2133 preferably communicateswith management work station 2140 (FIG. 11A) in order to enable operatorcontrol and monitoring of the power allocated to the various LAN nodesin various operational modes of the system.

[0275] Reference is now made to FIG. 13B, which is a simplified blockdiagram illustration of a hub and a power supply and managementsubsystem useful in the embodiment of FIG. 11B. Hub 2150 (FIG. 11B)preferably comprises a conventional, commercially available, LAN switch2184 which functions as a data communication switch/repeater and iscoupled to power supply interface 2186 forming part of power supplysubsystem 2180.

[0276] Power supply interface 2186 includes a filter unit 2187 whichincludes filters 372 as shown in FIG. 4B.

[0277] The filter unit 2187 is connected to a plurality of smart powerallocation and reporting circuits (SPEARs) 2374. Each SPEAR 2374 isconnected to power supply 2182 (FIG. 11B) for receiving electrical powertherefrom. It is appreciated that power supply 2182 may be physicallylocated externally of the power supply and management subsystem 2180.Power supply 2182 may be provided with a power failure backup facility,such as a battery connection.

[0278] Power management & control unit 2183 (FIG. 11B), preferablyincludes SPEAR controllers 2376 which are preferably connected via a bus2378 to a microprocessor 2380, a memory 2382 and communication circuitry2384, which typically includes a modem. The power management & controlunit 2183 is preferably operative to control the operation of all of thefilters and SPEARs in power supply interface 2186 as well as to controlthe operation of the power supply 2182.

[0279] Power management & control unit 2183 preferably communicates withmanagement work station 2190 (FIG. 11B) in order to enable operatorcontrol and monitoring of the power allocated to the various LAN nodesin various operational modes of the system.

[0280] Reference is now made to FIGS. 14A & 14B, which are simplifiedblock diagrams of two different node configurations useful in theembodiments of FIGS. 10A, 10B, 11A and 11B.

[0281] The circuitry seen in FIG. 14A includes circuitry which ispreferably embodied in a node, parts of which circuitry mayalternatively be embodied in a separator or connector associated withthat node.

[0282] The node, whatever its nature, for example any of nodes 2012-2020in FIG. 10A, 2062-2070 in FIG. 10B, 2112-2120 in FIG. 11A or 2162-2170in FIG. 11B, typically includes circuitry which is required for bothfull functionality and reduced functionality operation, here termed“essential circuitry” and designated by reference numeral 2400, andcircuitry which is not required for reduced functionality operation,here termed “non-essential circuitry” and designated by referencenumeral 2402. For example, if the node comprises an IP telephone, theessential circuitry 2400 includes that circuitry enabling a user tospeak and hear over the telephone, while the non-essential circuitry2402 provides ancillary functions, such as automatic redial, telephonedirectory and speakerphone functionality.

[0283] The circuitry 2400 and 2402 which is typically part of the nodeis indicated by reference numeral 2404. Other circuitry, which may ormay not be incorporated within the node will now be described. A powersupply 2406, such as power supply 510 (FIG. 7A) or 560 (FIG. 7B)receives electrical power via communication cabling from a separator,such as separator 508 shown in FIG. 7A or from a connector, such asconnector 558 shown in FIG. 7B. The power supply 2406 supplieselectrical power separately to the essential circuitry 2400 and via aswitch 2410 to the non-essential circuitry 2402. Switch 2410 may alsoreceive and control the transfer of electrical power from a power supply2412 which is connected to mains power.

[0284] Switch 2410 receives a control input from a controller 2414 whichis typically a conventional microcontroller providing a binary output.Controller 2414 receives a control input from a sensor 2416. Preferablycontroller 2414 also receives a control input from power supply 2412.

[0285] Sensor 2416 may be implemented in a number of possible ways. Itmay, for example, sense the voltage level of the electrical power beingsupplied to power supply 2406. Additionally or alternatively, it maysense a control signal transmitted thereto, such as a signal transmittedvia the communication cabling from the power management & control unit2038 via the combiner 2036 (FIG. 10A) or from similar circuitry in theembodiment of FIG. 11A. Alternatively, it may sense a control signaltransmitted thereto, such as a signal transmitted via the communicationcabling from the power management & control unit 2088 via the powersupply interface 2086 (FIG. 10B) or from similar circuitry in theembodiment of FIG. 11B.

[0286] The sensor 2416 may receive inputs from either or both the powerand data outputs of separator 508 (FIG. 7A) or connector 558 (FIG. 7B).The input that it receives from the data output of separator 508 orconnector 558 may be tapped from an input to the essential circuitrywhich may include control signal decoding functionality, but preferablymay be derived from an output of the essential circuitry which providesa decoded control signal.

[0287] The functionality of controller 2414 may be summarized asfollows: When the controller 2414 receives a control input from powersupply 2412 indicating that mains power is available, it operates switch2410 such that power is supplied to both essential circuitry 2400 andnon-essential circuitry 2402.

[0288] When mains power is not available via power supply 2412, butsensor 2416 indicates that sufficient power is available via thecommunications cabling, controller 2414 operates switch 2410 such thatpower is supplied to both essential circuitry 2400 and non-essentialcircuitry 2402.

[0289] When, however, mains power is not available via power supply 2412and sensor 2416 indicates that sufficient power is not available,controller operates switch 2410 such that adequate power is suppliedwith highest priority to the essential circuitry 2400. If additionalpower beyond that required by essential circuitry 2400 is alsoavailable, it may be supplied to the non-essential circuitry 2402 viaswitch 2410.

[0290] Alternatively, the operation of switch 2410 by the controller2414 may not be determined solely or at all by the power available, butrather solely by control signals sensed by sensor 2416, wholly orpartially independently of the available power.

[0291] Reference is now made to FIG. 14B. The circuitry seen in FIG. 14Bincludes circuitry which is preferably embodied in a node, parts ofwhich circuitry may alternatively be embodied in a separator orconnector associated with that node. A power supply 2436, such as powersupply 510 (FIG. 7A) or 560 (FIG. 7B) receives electrical power viacommunication cabling from a separator, such as separator 508 shown inFIG. 7A or from a connector, such as connector 558 shown in FIG. 7B. Thepower supply 2436 supplies electrical power via a switch 2438 to thecircuitry 2440 of the node. Switch 2438 may also receive electricalpower from a power supply 2442 which is connected to mains power.

[0292] Switch 2438 receives a control input from a controller 2444 whichis typically a conventional microcontroller providing a binary output.Controller 2444 receives a control input from a sensor 2446 as well as acontrol input from monitoring circuitry 2448. Monitoring circuitry 2448,which is continually powered by power supply 2436 or power supply 2442,senses a need of the LAN node to shift to full-functionality from sleepmode functionality. It may sense this need, for example, by receiving auser input indicating an intention to use the node or by receiving acontrol message via the communications cabling. Controller 2444 may alsoreceive a control input from power supply 2442.

[0293] Sensor 2446 may be implemented in a number of possible ways. Itmay, for example, sense the voltage level of the electrical power beingsupplied to power supply 2446. Additionally or alternatively, it maysense a control signal transmitted thereto, such as a signal transmittedvia the communication cabling from the power management & control unit2038 via the combiner 2036 (FIG. 10A) or from similar circuitry in theembodiment of FIG. 11A. Alternatively, it may sense a control signaltransmitted thereto, such as a signal transmitted via the communicationcabling from the power management & control unit 2088 via the powersupply interface 2086 (FIG. 10B) or from similar circuitry in theembodiment of FIG. 11B.

[0294] The functionality of controller 2444 may be summarized asfollows: In the absence of an indication to the contrary from themonitoring circuitry 2448 or from sensor 2446, the controller operatesswitch 2438 so that circuitry 2440 does not operate. When a suitableinput is received either from the monitoring circuitry 2448 or fromsensor 2446, indicating a need for operation of circuitry 2440, thecontroller 2444 operates switch 2438 to cause operation of circuitry2444.

[0295] Reference is now made to FIG. 15. The circuitry seen in FIG. 15includes circuitry which is preferably embodied in a node, parts ofwhich circuitry may alternatively be embodied in a separator associatedwith that node.

[0296] The node, whatever its nature, for example any of nodes 2012-2020in FIG. 10A, 2062-2070 in FIG. 10B, 2112-2120 in FIG. 11A or 2162-2170in FIG. 11B, typically includes circuitry which is required for bothfull functionality and reduced functionality operation, here termed“essential circuitry” and designated by reference numeral 2500, andcircuitry which is not required for reduced functionality operation,here termed “non-essential circuitry” and designated by referencenumeral 2502. For example, if the node comprises an IP telephone, theessential circuitry 2500 includes that circuitry enabling a user tospeak and hear over the telephone, while the non-essential circuitry2502 provides ancillary functions, such as automatic redial, telephonedirectory and speakerphone functionality.

[0297] The circuitry 2500 and 2502 which is typically part of the nodeis indicated by reference numeral 2504. Other circuitry, which may ormay not be incorporated within the node will now be described.

[0298] A power supply 2506, such as power supply 510 (FIG. 7A) or 560(FIG. 7B) receives electrical power via communication cabling from aseparator, such as separator 508 shown in FIG. 7A or connector 558 shownin FIG. 7B. The power supply 2506 supplies electrical power separatelyvia a switch 2508 to the essential circuitry 2500 and via a switch 2510to the non-essential circuitry 2502. Switches 2508 and 2510 may alsoreceive and control the transfer of electrical power from a power supply2512 which is connected to mains power.

[0299] Switches 2508 and 2510 each receive a control input from acontroller 2514 which is typically a conventional microcontrollerproviding a binary output. Controller 2514 receives a control input froma sensor 2516. Preferably controller 2514 also receives a control inputfrom power supply 2512.

[0300] Sensor 2516 may be implemented in a number of possible ways. Itmay, for example, sense the voltage level of the electrical power beingsupplied to power supply 2506. Additionally or alternatively, it maysense a control signal transmitted thereto, such as a signal transmittedvia the communication cabling from the power management & control unit2038 via the combiner 2036 (FIG. 10A) or from similar circuitry in theembodiment of FIG. 11A. Alternatively, it may sense a control signaltransmitted thereto, such as a signal transmitted via the communicationcabling from the power management & control unit 2088 via the powersupply interface 2086 (FIG. 10B) or from similar circuitry in theembodiment of FIG. 11B.

[0301] The sensor 2516 may receive inputs from either or both the powerand data outputs of separator 508 (FIG. 7A) or connector 558 (FIG. 7B).The input that it receives from the data output of separator 508 or fromconnector 558 may be tapped from an input to the essential circuitrywhich may include control signal decoding functionality, but preferablymay be derived from an output of the essential circuitry which providesa decoded control signal.

[0302] Monitoring circuitry 2540, which is continually powered by powersupply 2506 or power supply 2512, senses a need of the LAN node to shiftto full-functionality from sleep mode functionality. It may sense thisneed, for example, by receiving a user input indicating an intention touse the node or by receiving a control message via the communicationscabling.

[0303] The functionality of controller 2514 may be summarized asfollows: When the controller 2514 receives a control input from powersupply 2512 indicating that mains power is available, it operatesswitches 2508 and 2510 such that power is supplied to both essentialcircuitry 2500 and non-essential circuitry 2502.

[0304] When mains power is not available via power supply 2512, butsensor 2516 indicates that sufficient power is available via thecommunications cabling, controller 2514 operates switches 2508 and 2510such that power is supplied to both essential circuitry 2500 andnon-essential circuitry 2502.

[0305] When, however, mains power is not available via power supply 2512and sensor 2516 indicates that sufficient power is not available,controller operates switch 2508 such that adequate power is suppliedwith highest priority to the essential circuitry 2500. If additionalpower beyond that required by essential circuitry 2500 is alsoavailable, it may be supplied to the non-essential circuitry 2502 viaswitch 2510.

[0306] Alternatively, the operation of switch 2510 by the controller2514 may not be determined solely or at all by the power available, butrather solely by control signals sensed by sensor 2516, wholly orpartially independently of the available power.

[0307] In the absence of an indication to the contrary from themonitoring circuitry 2540 or from sensor 2516, the controller operatesswitch 2508 so that circuitry 2500 does not operate. When a suitableinput is received either from the monitoring circuitry 2540 or fromsensor 2516, indicating a need for operation of circuitry 2500, thecontroller 2514 operates switch 2508 to cause operation of circuitry2500.

[0308] In accordance with a preferred embodiment of the presentinvention, the power supply 2406 in the embodiment of FIG. 14A, 2436 inthe embodiment of FIGS. 14B and 2506 in the embodiment of FIG. 15 may beconstructed to include rechargeable energy storage elements. In such anarrangement, these power supplies provide limited back-up power for usein the case of a power failure or any other suitable circumstance. Theymay also enable intermittent operation of LAN nodes in situations whereonly very limited power may be transmitted over the communicationcabling.

[0309] Reference is now made to FIG. 16, which is a generalizedflowchart illustrating power management in both normal operation andreduced power modes of the networks of FIGS. 10A, 10B, 11A and 11B. Asseen in FIG. 16, the power management & control unit 2038 (FIG. 10A),2088 (FIG. 10B), 2133 (FIG. 1A) or 2138 (FIG. 1B) governs the supply ofpower to at least some LAN nodes via the communications cabling,preferably in accordance with a predetermined functionality which isdescribed hereinbelow with reference to FIG. 17.

[0310] The power management & control unit 2038 (FIG. 10A), 2088 (FIG.10B), 2133 (FIG. 11A) or 2138 (FIG. 11B) monitors and manages the powerconsumption of those LAN nodes. It senses overcurrent situations andeffects power cutoffs as appropriate. The power management & controlunit 2038 (FIG. 10A), 2088 (FIG. 10B), 2133 (FIG. 11A) or 2138 (FIG.11B) may operate in either an involuntary power management mode or avoluntary power management mode. Normally the mode of operation isselected at the time that the LAN is configured, however, it is possiblefor mode selection to take place thereafter.

[0311] In an involuntary power management mode of operation, if thepower management & control unit senses a situation of insufficient poweravailability for power transmission over the communications cabling tothe LAN nodes, it supplies a reduced amount of power to at least some ofthe LAN nodes and may also provide control messages or other controlinputs to the LAN nodes to cause them to operate in a reduced powermode. In a voluntary power management mode of operation, reduced poweravailability is mandated by management at certain times of reducedactivity, such as nights and weekends, in order to save energy costs

[0312] Reference is now made to FIG. 17, which illustrates a preferredmethodology for supply of electrical power to at least some of the LANnodes in accordance with the present invention.

[0313] Following initialization of hub 2010 (FIG. 10A), 20260 (FIG. 10B)or power supply and management subsystem 2130 (FIG. 11A), 2180 (FIG.11B) the communications cabling connection to nodes, to which it isintended to transmit power over the communications cabling, isinterrogated.

[0314] Initialization of hub 2010 (FIG. 10A), 20260 (FIG. 10B) orsubsystem 2130 (FIG. 11A), 2180 (FIG. 11B) preferably includesautomatically actuated test procedures which ensure proper operation ofthe elements of the hub 2010 (FIG. 10A), 20260 (FIG. 10B) or subsystem2130 (FIG. 11A), 2180 (FIG. 1B) communication with management workstation 2040 (FIG. 10A), 2090 (FIG. 10B), 2140 (FIG. 11A) or 2190 (FIG.11B) if present to determine desired operational parameters of the hubfor each node and setting up an internal data base including desiredoperational parameters for each node. During normal operation of thesystem, the various operational parameters for each node may be modifiedby an operator employing the management work station 2040 (FIG. 10A),2090 (FIG. 10B), 2140 (FIG. 11A), 2190 (FIG. 11B).

[0315] The interrogation is described hereinbelow in greater detail withreference to FIGS. 18A and 18B.

[0316] If the node being interrogated is determined to havepower-over-LAN type characteristics and is classified in the internaldata base as a node to which it is intended to transmit power over thecommunications cabling, the SPEAR parameters are set based on thecontents of the internal data base and power is transmitted to the nodevia the communications cabling. Where appropriate, suitable signalingmessages are sent to the remote node and the status of the lineconnected to the node is reported to the management work station 2040.

[0317] The foregoing procedure is then repeated sequentially for eachline of the hub 2110 or subsystem 2130, to which it is intended totransmit power over the communications cabling.

[0318] Reference is now made to FIGS. 18A and 18B, which together are aflowchart illustrating a preferred embodiment of the interrogation andinitial power supply functionality which appears in FIG. 17.

[0319] As seen in FIGS. 18A & 18B, initially the voltage is measured atthe output of the SPEAR 224 (FIG. 3A), 274 (FIG. 3B), 324 (FIG. 4A) or374 (FIG. 4B) corresponding to a line to which it is intended totransmit power over the communications cabling. If the absolute value ofthe voltage is higher than a predetermined programmable threshold V1,the line is classified as having a voltage present thereon from anexternal source. In such a case power is not supplied thereto over thecommunications cabling.

[0320] If the absolute value of the voltage is not higher than thepredetermined programmable threshold V1, the SPEAR current limit 10 isset to a predetermined programmable value IL1. SPEAR switch 408 (FIG. 5)is turned ON.

[0321] The voltage and the current at the output of the SPEAR aremeasured, typically at three predetermined programmable times T1, T2 andT3. Times T1, T2 and T3 are typically determined by a time constantdetermined by the inductance of typical NIC transformers and the maximumroundtrip DC resistance of a maximum allowed length of communicationscabling between the hub and a node. Typically, T1, T2 and T3 are equalto 1, 2 and 10 times the above time constant.

[0322] Typical values for T1, T2 and T3 are 4 msec, 8 msec and 40 msec,respectively.

[0323] Based on these measurements the status of the node and the lineto which it is connected are determined. A typical set of determinationsis set forth hereinbelow: NO LOAD  WHEN Vout > V2 AND THE ABSOLUTE VALUEOF IO < I2 FOR ALL T1, T2, T3 SHORT CIRCUIT WHEN Vout < V3 AND THEABSOLUTE VALUE OF IO > I3 FOR ALL T1, T2, T3 NIC LOAD WHEN VoutT3 < V4AND THE ABSOLUTE VALUE OF IOT1<IOT2<IOT3 POL LOAD WHEN VoutT1>V5 ANDVoutT2>V5 AND VoutT3>V5     AND THE ABSOLUTE VALUE OF IOT1>I5 OR       THE ABSOLUTE VALUE OF IOT2>I5 OR        THE ABSOLUTE VALUE OFIOT3>I5.

[0324] WHERE

[0325] A NO LOAD condition is one in which a node is not connected tothe line.

[0326] A SHORT CIRCUIT condition is one in which a short circuit existsacross the positive and negative conductors of the line upstream of thenode or in the node.

[0327] A NIC LOAD condition is one in which a Network Interface Cardline transformer is connected across the line at the node.

[0328] A POL LOAD condition is one in which a Power Over LAN separatoris connected across the line at the node.

[0329] V0 is the voltage at the output of the SPEAR.

[0330] V1 is a predetermined programmable value which is preferablyarrived at by measuring the highest peak value of voltage Vout for aperiod of a few minutes when switch 408 is OFF. This value is typicallymultiplied by 2 to arrive at V1. V1 is typically equal to 3 Volts.

[0331] V2 is a predetermined programmable value which is preferablyarrived at by measuring the lowest value of voltage Vout for a period ofa few minutes when switch 408 is ON and when no load is connectedbetween +Vout and-Vout at the output of each coupler 220 (FIG. 3A) and320 (FIG. 4A). A typical value of V2 is 80% of Vin.

[0332] V3 is a predetermined programmable value which is preferablyarrived at by measuring the highest peak value of voltage Vout for aperiod of a few minutes when switch 408 is ON and when a resistance,which corresponds to the maximum roundtrip DC resistance of a maximumallowed length of communications cabling between the hub and a node,typically 50 ohms, is connected between +Vout and −Vout at the output ofeach coupler 220 (FIG. 3A) and 320 (FIG. 4A). This value is typicallymultiplied by 2 to arrive at V1. V1 is typically equal to 3 Volts.

[0333] V4 is a predetermined programmable value which is preferablyarrived at by measuring the highest peak value of voltage Vout for aperiod of a few minutes when switch 408 is ON and when a resistance,which corresponds to the maximum roundtrip DC resistance of a maximumallowed length of communications cabling between the hub and a node andthe resistance of a NIC transformer, typically totaling 55 ohms, isconnected between +Vout and −Vout at the output of each coupler 220(FIG. 3A) and 320 (FIG. 4A). This value is typically multiplied by 2 toarrive at V1. V1 is typically equal to 3 Volts.

[0334] V5 is a predetermined programmable value which is preferably 50%of Vin, which represents a typical threshold value of Vin at which powersupply 510 (FIG. 7) commence operation.

[0335] VoutT1 is Vout measured at time T1;

[0336] VoutT2 is Vout measured at time T2;

[0337] VoutT3 is Vout measured at time T3;

[0338] IO is the current flowing +Vout to −Vout which is measured bysensor 402 (FIG. 5)

[0339] IL1 is the predetermined programmable value of the current limitof switch 408 (FIG. 5) and is determined by the maximum allowable DCcurrent through the NIC transformer which does not result in saturationor burnout thereof. IL1 is typically in the vicinity of 10 mA.

[0340] I2 is a predetermined programmable value which is preferablyarrived at by measuring the maximum peak value of the current 10 for aperiod of a few minutes when switch 408 is ON and when no load isconnected between +Vout and −Vout at the output of each coupler 220(FIG. 3A) and 320 (FIG. 4A). A typical value of 12 is 1 mA.

[0341] I3 is a predetermined programmable value which is preferablyarrived at by measuring the minimum value of the current 10 for a periodof a few minutes when switch 408 is ON and when a resistance, whichcorresponds to the maximum roundtrip DC resistance of a maximum allowedlength of communications cabling between the hub and a node, typically50 ohms, is connected between +Vout and −Vout at the output of eachcoupler 220 (FIG. 3A) and 320 (FIG. 4A). I3 is typically equal to 80% ofIL1.

[0342] I5 is a predetermined programmable value which is preferablyarrived at by measuring the maximum peak value of the current 10 for aperiod of a few minutes when switch 408 is ON and when no load isconnected between +Vout and −Vout at the output of each coupler 220(FIG. 3A) and 320 (FIG. 4A). This maximum peak value is multiplied by afactor, typically 2. A typical value of 15 is 2 mA.

[0343] IOT1 is IO measured at time T1;

[0344] IOT2 is IO measured at time T2;

[0345] IOT3 is IO measured at time T3;

[0346] Reference is now made to FIGS. 19A-19D, 20A-20D, 21A-21D,22A-22D, 23A-23D and 24A-24D, which illustrate various functionalitiesfor monitoring and managing power consumption in accordance with apreferred embodiment of the present invention. Most or all of thefunctionalities described hereinbelow employ a basic monitoring andmanaging technique which is now described:

[0347] In accordance with a preferred embodiment of the presentinvention, the functionality for monitoring and managing powerconsumption during normal operation includes sensing current on alllines. This is preferably carried out in a generally cyclic manner. Thesensed current is compared with programmably predetermined referencevalues for each line. Alternatively or additionally, voltage may besensed and employed for this purpose. On the basis of this comparison,each node is classified as being over-current, under-current or normal.The over-current classification may have programmably adjustablethresholds, such as high over-current, and regular over-current. Thenormal classification may have sub-classifications, such as active mode,sleep mode, and low-power mode.

[0348] The system is operative to control the operation of nodesclassified as being over-current in the following manner: If the currentat a node exceeds a regular over current threshold for at least apredetermined time, power to that node is cut off after thepredetermined time. In any event, current supplied to a node is notpermitted to exceed the high over-current threshold. In accordance witha preferred embodiment of the present invention, various intermediatethresholds may be defined between the regular over-current threshold andthe high over-current threshold and the aforesaid predetermined time tocut-off is determined as a function of which of such intermediatethresholds is exceeded.

[0349] The system is operative to control the operation of nodesclassified as being under-current in the following manner: Within arelatively short predetermined time following detection of anunder-current node, which predetermined time is selected to avoidundesired response to noise, supply of current to such node isterminated.

[0350] In parallel to the functionality described hereinabove, theoverall current flow to all of the nodes over all of the lines ismonitored. This monitoring may take place in a centralized manner oralternatively may be based on an extrapolation of information receivedin the line-by-line monitoring described hereinabove.

[0351] The sensed overall current is compared with a programmablypredetermined reference value. On the basis of this comparison, theentire hub and the nodes connected thereto are together classified asbeing over-current or normal. The over-current classification may haveprogrammably adjustable thresholds, such as high over-current, andregular over-current.

[0352] The system is operative to control the operation of hubsclassified as being over-current in the following manner: If the overallcurrent exceeds a regular overall over-current threshold for at least apredetermined time, power to at least some nodes is either reduced orcut off after the predetermined time. In any event, the overall currentis not permitted to exceed the high overall over-current threshold. Inaccordance with a preferred embodiment of the present invention, variousintermediate thresholds may be defined between the regular overallover-current threshold and the high overall over-current threshold andthe aforesaid predetermined time to cut-off is determined as a functionof which of such intermediate thresholds is exceeded.

[0353] Additionally in parallel to the functionality describedhereinabove, the system is operative to report either continuously orintermittently, the current level classification of each node and of theentire hub to an external monitoring system.

[0354] Further in parallel to the functionality described hereinabove,the system is operative to notify nodes of the impending change in thecurrent supply thereto.

[0355] Reference is now made to FIGS. 19A, 19B, 19C and 19D, which aregeneralized flowcharts each illustrating one possible mechanism for fullor no functionality operation in an involuntary power management step inthe flowchart of FIG. 16.

[0356]FIG. 19A illustrates a basic technique useful for full or nofunctionality operation in involuntary power management in accordancewith a preferred embodiment of the present invention. As seen in FIG.19A, the system initially determines the total power available to it aswell as the total power that it is currently supplying to all nodes. Therelationship between the current total power consumption (TPC) to thecurrent total power availability (TPA) is then determined.

[0357] If TPC/TPA is less than typically 0.8, additional nodes aresupplied full power one-by-one on a prioritized basis. If TPC/TPA isgreater than typically 0.95, power to individual nodes is disconnectedone-by-one on a prioritized basis.

[0358] If TPC/TPA is equal to or greater than typically 0.8 but lessthan or equal to typically 0.95, an inquiry is made as to whether a newnode requires power. If so, and a node having a lower priority iscurrently receiving power, the lower priority node is disconnected frompower and the higher priority node is connected to power.

[0359]FIG. 19B illustrates a technique useful for full or nofunctionality operation with emergency override in involuntary powermanagement in accordance with a preferred embodiment of the presentinvention. The technique of FIG. 19B can be used in the environment ofthe functionality of FIG. 19A.

[0360] As seen in FIG. 19B, the system senses an emergency need forpower at a given node. In such a case, the given node is assigned thehighest priority and the functionality of FIG. 19A is applied. Once theemergency situation no longer exists, the priority of the given node isreturned to its usual priority and the functionality of FIG. 19Aoperates accordingly.

[0361]FIG. 19C illustrates a technique useful for full or nofunctionality operation having queue-controlled priority in involuntarypower management in accordance with a preferred embodiment of thepresent invention. As seen in FIG. 19C, the system initially determinesthe total power available to it as well as the total power that it iscurrently supplying to all nodes. The relationship between the currenttotal power consumption (TPC) to the current total power availability(TPA) is then determined.

[0362] If TPC/TPA is less than typically 0.8, additional nodes aresupplied full power one-by-one on a queue-controlled, prioritized basis,typically on a first come, first served basis. If TPC/TPA is greaterthan typically 0.95, power to individual nodes is disconnectedone-by-one on a prioritized basis.

[0363] If TPC/TPA is equal to or greater than typically 0.8 but lessthan or equal to typically 0.95, an inquiry is made as to whether a newnode requires power. If so, that node is added to the bottom of thequeue.

[0364]FIG. 19D illustrates a technique useful for full or nofunctionality operation having queue-controlled priority in involuntarypower management in accordance with a preferred embodiment of thepresent invention. As seen in FIG. 19D, the system initially determinesthe total power available to it as well as the total power that it iscurrently supplying to all nodes. The relationship between the currenttotal power consumption (TPC) to the current total power availability(TPA) is then determined.

[0365] If TPC/TPA is less than typically 0.8, additional nodes aresupplied full power one-by-one on a time-sharing, prioritized basis,typically on a basis that the node having the longest duration of use iscut off first. If TPC/TPA is greater than typically 0.95, power toindividual nodes is disconnected one-by-one on a prioritized basis.

[0366] If TPC/TPA is equal to or greater than typically 0.8 but lessthan or equal to typically 0.95, an inquiry is made as to whether a newnode requires power. If so, and a node having a lower priority, in thesense that it has been receiving power for a longer time, which is abovea predetermined minimum time, is currently receiving power, the lowerpriority node is disconnected from power and the higher priority node isconnected to power.

[0367] It is appreciated that normally it is desirable that the node beinformed in advance in a change in the power to be supplied thereto.This may be accomplished by signally along the communications cabling ina usual data transmission mode or in any other suitable mode.

[0368] Reference is now made to FIGS. 20A, 20B, 20C and 20D, which aregeneralized flowcharts each illustrating one possible mechanism for fullor reduced functionality operation in an involuntary power managementstep in the flowchart of FIG. 16.

[0369]FIG. 20A illustrates a basic technique useful for full or reducedfunctionality operation in involuntary power management in accordancewith a preferred embodiment of the present invention. As seen in FIG.20A, the system initially determines the total power available to it aswell as the total power that it is currently supplying to all nodes. Therelationship between the current total power consumption (TPC) to thecurrent total power availability (TPA) is then determined.

[0370] If TPC/TPA is less than typically 0.8, additional nodes aresupplied full power one-by-one on a prioritized basis. If TPC/TPA isgreater than typically 0.95, power to individual nodes is reducedone-by-one on a prioritized basis.

[0371] If TPC/TPA is equal to or greater than typically 0.8 but lessthan or equal to typically 0.95, an inquiry is made as to whether a newnode requires additional power. If so, and a node having a lowerpriority is currently receiving power, the lower priority node has itspower supply reduced and the higher priority node is provided withadditional power.

[0372]FIG. 20B illustrates a technique useful for full or reducedfunctionality operation with emergency override in involuntary powermanagement in accordance with a preferred embodiment of the presentinvention. The technique of FIG. 20B can be used in the environment ofthe functionality of FIG. 20A.

[0373] As seen in FIG. 20B, the system senses an emergency need foradditional power at a given node. In such a case, the given node isassigned the highest priority and the functionality of FIG. 20A isapplied. Once the emergency situation no longer exists, the priority ofthe given node is returned to its usual priority and the functionalityof FIG. 20A operates accordingly.

[0374]FIG. 20C illustrates a technique useful for full or reducedfunctionality operation having queue-controlled priority in involuntarypower management in accordance with a preferred embodiment of thepresent invention. As seen in FIG. 20C, the system initially determinesthe total power available to it as well as the total power that it iscurrently supplying to all nodes. The relationship between the currenttotal power consumption (TPC) to the current total power availability(TPA) is then determined.

[0375] If TPC/TPA is less than typically 0.8, additional nodes aresupplied additional power one-by-one on a queue-controlled, prioritizedbasis, typically on a first come, first served basis. If TPC/TPA isgreater than typically 0.95, power to individual nodes is reducedone-by-one on a prioritized basis.

[0376] If TPC/TPA is equal to or greater than typically 0.8 but lessthan or equal to typically 0.95, an inquiry is made as to whether a newnode requires additional power. If so, that node is added to the bottomof the queue.

[0377]FIG. 20D illustrates a technique useful for full or reducedfunctionality operation having queue-controlled priority in involuntarypower management in accordance with a preferred embodiment of thepresent invention. As seen in FIG. 20D, the system initially determinesthe total power available to it as well as the total power that it iscurrently supplying to all nodes. The relationship between the currenttotal power consumption (TPC) to the current total power availability(TPA) is then determined.

[0378] If TPC/TPA is less than typically 0.8, additional nodes aresupplied additional power one-by-one on a time-sharing, prioritizedbasis, typically on a basis that the node having the longest duration ofuse is cut off first. If TPC/TPA is greater than typically 0.95, powerto individual nodes is disconnected one-by-one on a prioritized basis.

[0379] If TPC/TPA is equal to or greater than typically 0.8 but lessthan or equal to typically 0.95, an inquiry is made as to whether a newnode requires additional power. If so, and a node having a lowerpriority, in the sense that it has been receiving power for a longertime, which is above a predetermined minimum time, is currentlyreceiving full power, the lower priority node has its power supplyreduced and the higher priority node is provided with additional power.

[0380] Reference is now made to FIGS. 21A, 21B, 21C and 21D aregeneralized flowcharts each illustrating one possible mechanism for nodeinitiated sleep mode operation in a voluntary power management step inthe flowchart of FIG. 16.

[0381]FIG. 21A illustrates a situation wherein a node operates in asleep mode as the result of lack of activity for at least apredetermined amount of time. As seen in FIG. 21A, the time duration TD1since the last activity of the node is measured. If TD1 exceedstypically a few seconds or minutes, in the absence of a user or systeminput contraindicating sleep mode operation, the node then operates in asleep mode, which normally involves substantially reduced powerrequirements.

[0382]FIG. 21B illustrates a situation wherein a node operates in asleep mode as the result of lack of communication for at least apredetermined amount of time. As seen in FIG. 21B, the time duration TD2since the last communication of the node is measured. If TD2 exceedstypically a few seconds or minutes, in the absence of a user or systeminput contraindicating sleep mode operation, the node then operates in asleep mode, which normally involves substantially reduced powerrequirements.

[0383]FIG. 21C illustrates a situation wherein a node operates in asleep mode in response to clock control, such that the node is activewithin a periodically occurring time slot, absent an input from thesystem or the user. As seen in FIG. 21C, the time slots are defined astimes TD3 while the remaining time is defined as TD4. The nodedetermines whether it is currently within the time slot TD3. If not,i.e. during times TD4, it operates in the sleep mode.

[0384]FIG. 21D illustrates a situation wherein a node operates in asleep mode as the result of a sensed fault condition. As seen in FIG.21D, the node periodically performs a self-test. The self test may be,for example, an attempt to communicate with the hub. If the node passesthe test, it operates normally. If the node fails the test, it operatesin the sleep mode.

[0385] Reference is now made to FIGS. 22A, 22B, 22C and 22D, which aregeneralized flowcharts each illustrating one possible mechanism for hubinitiated sleep mode operation in a voluntary power management step inthe flowchart of FIG. 16.

[0386]FIG. 22A illustrates a situation wherein a node operates in asleep mode as the result of lack of activity for at least apredetermined amount of time. As seen in FIG. 22A, the time duration TD1since the last activity of the node as sensed by the hub is measured. IfTD1 exceeds typically a few seconds or minutes, in the absence of a useror system input contraindicating sleep mode operation, the node thenoperates in a sleep mode, which normally involves substantially reducedpower requirements.

[0387]FIG. 22B illustrates a situation wherein a node operates in asleep mode as the result of lack of communication for at least apredetermined amount of time. As seen in FIG. 22B, the time duration TD2since the last communication of the node as sensed by the hub ismeasured. If TD2 exceeds typically a few seconds or minutes, in theabsence of a user or system input contraindicating sleep mode operation,the node then operates in a sleep mode, which normally involvessubstantially reduced power requirements.

[0388]FIG. 22C illustrates a situation wherein a node operates in asleep mode in response to clock control from the hub, such that the nodeis active within a periodically occurring time slot, absent an inputfrom the system or the user. As seen in FIG. 22C, the time slots aredefined as times TD3 while the remaining time is defined as TD4. Thenode determines whether it is currently within the time slot TD3. Ifnot, i.e. during times TD4, it operates in the sleep mode.

[0389]FIG. 22D illustrates a situation wherein a node operates in asleep mode as the result of a fault condition sensed by the hub. As seenin FIG. 22D, the hub periodically performs a test of the node. The selftest may be, for example, an attempt to communicate with the hub. If thenode passes the test, it operates normally. If the node fails the test,it operates in the sleep mode.

[0390] Reference is now made to FIGS. 23A, 23B, 23C and 23D, which aregeneralized flowcharts each illustrating one possible mechanism for fullor no functionality operation in a voluntary power management step inthe flowchart of FIG. 16.

[0391]FIG. 23A illustrates a basic technique useful for full or nofunctionality operation in voluntary power management in accordance witha preferred embodiment of the present invention. As seen in FIG. 23A,the system initially determines the total power allocated to it as wellas the total power that it is currently supplying to all nodes. Therelationship between the current total power consumption (TPC) to thecurrent total power allocation (TPL) is then determined.

[0392] If TPC/TPL is less than typically 0.8, additional nodes aresupplied full power one-by-one on a prioritized basis. If TPC/TPL isgreater than typically 0.95, power to individual nodes is disconnectedone-by-one on a prioritized basis.

[0393] If TPC/TPL is equal to or greater than typically 0.8 but lessthan or equal to typically 0.95, an inquiry is made as to whether a newnode requires power. If so, and a node having a lower priority iscurrently receiving power, the lower priority node is disconnected frompower and the higher priority node is connected to power.

[0394]FIG. 23B illustrates a technique useful for full or nofunctionality operation with emergency override in voluntary powermanagement in accordance with a preferred embodiment of the presentinvention. The technique of FIG. 23B can be used in the environment ofthe functionality of FIG. 23A.

[0395] As seen in FIG. 23B, the system senses an emergency need forpower at a given node. In such a case, the given node is assigned thehighest priority and the functionality of FIG. 23A is applied. Once theemergency situation no longer exists, the priority of the given node isreturned to its usual priority and the functionality of FIG. 23Aoperates accordingly.

[0396]FIG. 23C illustrates a technique useful for full or nofunctionality operation having queue-controlled priority in voluntarypower management in accordance with a preferred embodiment of thepresent invention. As seen in FIG. 23C, the system initially determinesthe total power allocated to it as well as the total power that it iscurrently supplying to all nodes. The relationship between the currenttotal power consumption (TPC) to the current total power allocation(TPL) is then determined.

[0397] If TPC/TPL is less than typically 0.8, additional nodes aresupplied full power one-by-one on a queue-controlled, prioritized basis,typically on a first come, first served basis. If TPC/TPL is greaterthan typically 0.95, power to individual nodes is disconnectedone-by-one on a prioritized basis.

[0398] If TPC/TPL is equal to or greater than typically 0.8 but lessthan or equal to typically 0.95, an inquiry is made as to whether a newnode requires power. If so, that node is added to the bottom of thequeue.

[0399]FIG. 23D illustrates a technique useful for full or nofunctionality operation having queue-controlled priority in voluntarypower management in accordance with a preferred embodiment of thepresent invention. As seen in FIG. 23D, the system initially determinesthe total power allocated to it as well as the total power that it iscurrently supplying to all nodes. The relationship between the currenttotal power consumption (TPC) to the current total power allocation(TPL) is then determined.

[0400] If TPC/TPL is less than typically 0.8, additional nodes aresupplied full power one-by-one on a time-sharing, prioritized basis,typically on a basis that the node having the longest duration of use iscut off first. If TPC/TPL is greater than typically 0.95, power toindividual nodes is disconnected one-by-one on a prioritized basis.

[0401] If TPC/TPL is equal to or greater than typically 0.8 but lessthan or equal to typically 0.95, an inquiry is made as to whether a newnode requires power. If so, and a node having a lower priority, in thesense that it has been receiving power for a longer time, which is abovea predetermined minimum time, is currently receiving power, the lowerpriority node is disconnected from power and the higher priority node isconnected to power.

[0402] It is appreciated that normally it is desirable that the node beinformed in advance in a change in the power to be supplied thereto.This may be accomplished by signally along the communications cabling ina usual data transmission mode or in any other suitable mode.

[0403] Reference is now made to FIGS. 24A, 24B, 24C and 24D, which aregeneralized flowcharts each illustrating one possible mechanism for fullor reduced functionality operation in a voluntary power management stepin the flowchart of FIG. 16.

[0404]FIG. 24A illustrates a basic technique useful for full or reducedfunctionality operation in voluntary power management in accordance witha preferred embodiment of the present invention. As seen in FIG. 24A,the system initially determines the total power allocated to it as wellas the total power that it is currently supplying to all nodes. Therelationship between the current total power consumption (TPC) to thecurrent total power allocation (TPL) is then determined.

[0405] If TPC/TPL is less than typically 0.8, additional nodes aresupplied full power one-by-one on a prioritized basis. If TPC/TPL isgreater than typically 0.95, power to individual nodes is reducedone-by-one on a prioritized basis.

[0406] If TPC/TPL is equal to or greater than typically 0.8 but lessthan or equal to typically 0.95, an inquiry is made as to whether a newnode requires additional power. If so, and a node having a lowerpriority is currently receiving power, the lower priority node has itspower supply reduced and the higher priority node is provided withadditional power.

[0407]FIG. 24B illustrates a technique useful for full or reducedfunctionality operation with emergency override in voluntary powermanagement in accordance with a preferred embodiment of the presentinvention. The technique of FIG. 24B can be used in the environment ofthe functionality of FIG. 24A.

[0408] As seen in FIG. 24B, the system senses an emergency need foradditional power at a given node. In such a case, the given node isassigned the highest priority and the functionality of FIG. 24A isapplied. Once the emergency situation no longer exists, the priority ofthe given node is returned to its usual priority and the functionalityof FIG. 24A operates accordingly.

[0409]FIG. 24C illustrates a technique useful for full or reducedfunctionality operation having queue-controlled priority in voluntarypower management in accordance with a preferred embodiment of thepresent invention. As seen in FIG. 24C, the system initially determinesthe total power allocated to it as well as the total power that it iscurrently supplying to all nodes. The relationship between the currenttotal power consumption (TPC) to the current total power allocation(TPL) is then determined.

[0410] If TPC/TPL is less than typically 0.8, additional nodes aresupplied additional power one-by-one on a queue-controlled, prioritizedbasis, typically on a first come, first served basis. If TPC/TPL isgreater than typically 0.95, power to individual nodes is reducedone-by-one on a prioritized basis.

[0411] If TPC/TPL is equal to or greater than typically 0.8 but lessthan or equal to typically 0.95, an inquiry is made as to whether a newnode requires additional power. If so, that node is added to the bottomof the queue.

[0412]FIG. 24D illustrates a technique useful for full or additionalfunctionality operation having queue-controlled priority in voluntarypower management in accordance with a preferred embodiment of thepresent invention. As seen in FIG. 24D, the system initially determinesthe total power allocated to it as well as the total power that it iscurrently supplying to all nodes. The relationship between the currenttotal power consumption (TPC) to the current total power allocation(TPL) is then determined.

[0413] If TPC/TPL is less than typically 0.8, additional nodes aresupplied additional power one-by-one on a time-sharing, prioritizedbasis, typically on a basis that the node having the longest duration ofuse is cut off first. If TPC/TPL is greater than typically 0.95, powerto individual nodes is disconnected one-by-one on a prioritized basis.

[0414] If TPC/TPL is equal to or greater than typically 0.8 but lessthan or equal to typically 0.95, an inquiry is made as to whether a newnode requires additional power. If so, and a node having a lowerpriority, in the sense that it has been receiving power for a longertime, which is above a predetermined minimum time, is currentlyreceiving full power, the lower priority node has its power supplyreduced and the higher priority node is provided with additional power.

[0415] It will be appreciated by persons skilled in the art that thepresent invention is not limited by what has been particularly shown anddescribed hereinabove. Rather the scope of the present inventionincludes both combinations and sub-combinations of various featuresdescribed hereinabove as well as modifications and variations thereofwhich would occur to persons skilled in the art and which are not in theprior art.

What is claimed is:
 1. A power supply subsystem configured forconnection between a LAN switch and at least one node, the power supplysubsystem providing electrical power to the at least node overcommunication cabling, the power supply subsystem comprising: amanagement and control unit; at least one port for connection to a LANswitch; a combiner combining power into the communication cablingsubstantially without interfering with data communication between theLAN switch via the at least one port and the at least one node; andcurrent limiting circuitry controlling current of said power deliveredinto said communication cabling via said combiner, wherein saidmanagement and control unit is operative to interrogate the at least onenode to which it is intended to transmit power over the communicationcabling in order to determine whether the node's characteristics allowit to receive power over the communication cabling.
 2. A power supplysubsystem according to claim 1, wherein said current limiting circuitryis operative to provide a first current limit level which is neverexceeded, and a second current limit level which is not exceeded formore than a predetermined period of time.
 3. A power supply subsystemaccording to claim 2, wherein said interrogation of the at least onenode includes measuring the voltage across the communication cablingconnected to the at least one node and determining whether said measuredvoltage is within a predefined range.
 4. A power supply subsystemaccording to claim 3, wherein in the event that said measured voltage iswithin said predetermined range, the at least one node is classified asa Power over LAN node.
 5. A power supply subsystem according to claim 2,wherein said interrogation of the at least node comprises measuring thevoltage across the communication cabling connected to the at least nodeand determining whether said measured voltage exceeds a predeterminedthreshold.
 6. A power supply subsystem according to claim 1, whereinsaid combiner comprises at least one coupler.
 7. A power supplysubsystem according to claim 1, wherein said interrogation of the atleast one node comprises measuring the voltage across the communicationcabling connected to the at least one node and determining whether saidmeasured voltage is within a predefined range.
 8. A power supplysubsystem according to claim 7, wherein in the event said measuredvoltage is within said predefined range, the at least one node isclassified as a Power over LAN node.
 9. A power supply subsystemaccording to claim 1, wherein said interrogation of the at least onenode includes measuring the voltage across the communication cablingconnected to the at least one node and determining whether said measuredvoltage exceeds a predetermined threshold.
 10. A power supply subsystemaccording to claim 1, wherein said management and control unit isfurther operable to output a report pertaining to the status of the atleast one node.
 11. A power supply subsystem according to claim 10,wherein said report includes a report of at least one characteristic ofthe at least one node.
 12. A power supply subsystem according to claim11, wherein said at least one characteristic comprises an indication ofpower consumption of the at least one node.
 13. A power supply subsystemaccording to claim 1, wherein said power is combined onto wire pairs ofthe communication cabling providing data communication between the atleast one node and the LAN switch.
 14. A power supply subsystemaccording to claim 1, wherein said power is transmitted over wire pairsof said communication cabling providing data communication between theat least one node and the LAN switch.
 15. A power supply subsystemaccording to claim 1, further comprising a power supply, said combinercombining power from said power supply into the communication cabling.16. A power supply subsystem according to claim 1, wherein saidmanagement and control unit is further operative to determine the statusof the associated communication cabling over which it is intended totransmit power.
 17. A local power supply subsystem according to claim16, wherein said interrogation and said status determination is achievedby a plurality of measurements of at least one of voltage and current,said plurality of measurements being accomplished at a plurality oftimes.
 18. A power supply subsystem configured for connection between aLAN switch and at least one node, the power supply subsystem providingelectrical power to the at least node over communication cabling, thepower supply subsystem comprising: a management and control unit; atleast one port for data connection to a LAN switch; at least one portfor connection of communication cabling to the at least one node; acombiner combining power into the communication cabling substantiallywithout interfering with data communication between the LAN switch andthe at least one node; and current limiting circuitry controllingcurrent of said power delivered into said communication cabling via saidcombiner, wherein said management and control unit is operative tointerrogate the at least one node to which it is intended to transmitpower over the communication cabling in order to determine whether thenode's characteristics allow it to receive power over the communicationcabling.
 19. A power supply subsystem configured for connection betweena LAN switch and at least one node, the power supply subsystem providingelectrical power to the at least node over communication cabling, thepower supply subsystem comprising: a management and control unit; atleast one port for connection to a LAN switch; a combiner combiningpower into the communication cabling substantially without interferingwith data communication between the LAN switch via the at least one portand the at least one node; and current limiting circuitry controllingcurrent of said power delivered into said communication cabling via saidcombiner, said current limiting circuitry being operative to provide afirst current limit level which is never exceeded, and a second currentlimit level which is not exceeded for more than a predetermined periodof time, wherein said management and control unit is operative tointerrogate the at least one node to which it is intended to transmitpower over the communication cabling in order to determine whether thenode's characteristics allow it to receive power over the communicationcabling.
 20. A power supply subsystem configured for connection betweena LAN switch and at least one node, the power supply subsystem providingelectrical power to the at least node over communication cabling, thepower supply subsystem comprising: a management and control unit; atleast one port for data connection to a LAN switch; a combiner combiningpower into the communication cabling substantially without interferingwith data communication between the LAN switch and the at least onenode; and current limiting circuitry controlling current of said powerdelivered into said communication cabling via said combiner, saidcurrent limiting circuitry providing a first current limit level whichis never exceeded, and a second current limit level which is notexceeded for more than a predetermined period of time, wherein saidmanagement and control unit is operative to interrogate the at least onenode to which it is intended to transmit power over the communicationcabling in order to determine whether the node's characteristics allowit to receive power over the communication cabling.